From what we know PD does not receive direct profits from selling their games. What keeps PD afloat is (practically) only Sony, who gives them a yearly budget for whatever they might be working on.
That's why it's been reported GT5 cost 60 millions to be made. The idea is PD had $10 million a year as budget for the whole company, so 10x6.
(I know this isn't really correct due that they released some other games in that period and that there's many more costs to be considered than just making the very game too, but that's how the calculation was made back then).
Secondly, Sony's best interest is to have console seller games and those are the exclusives. Also before Driveclub the GT series was the only stable franchise Sony had in the entire racing genre, so not having a racing game would mean losing the entire racing enthusiasts crowd (several millions) and losing the opportunity of having a game of a genre that is perfect for showing off the newest consoles' graphics capabilities.
Those two are the biggest, if not only reasons why PD exists and why Sony finances it.
With that said, as long as the Playstation exists there's absolutely no way a Gran Turismo game will ever, ever be released for something else than the latest Playstation. Also, if there are no new Playstations then maybe other Gran Turismo branded games could come out for other systems, but they wouldn't be the same by any means so in actuality they wouldn't be Gran Turismo games, so GT dies with the Playstation (I touch that matter at the end of this post).
Even in the case GT7 for the PS4 could be ported to the PC, latest Xbox and Nintendo consoles by just copypasting it (ctrl+c ctrl+v) and without any optimizations done or anything else, that increase in copies sold still wouldn't be worth it for Sony.
What I want to say is that this is not a technical matter, but of how Sony and PD are run.
For a better example lets take the Forza series. Currently that franchise's games cost way more than the GT series' to be made (so more than $10m a year) and still they sell way less anyway (many times less), but at the end of the day it's worth the money for Microsoft (controller of Turn 10) because the Forza series is a console seller and Forza is their only stable racing franchise.
Yes, they have same architecture, but it stops there.
Developers don't exploit PC to the fullest because of parameters mentioned above. While consoles, yes because it's the same for everybody.
I'm no technical guy whatsoever but I think you are wrong because it's actuality the opposite: the problem is not the PC release but the one for consoles.
Just like any other game, the GT series is made on a PC and made to work on a PC. It is afterwards that the game is made to run on a console. That means what is expensive and tiresome (both very much so) is making GT6 run on the PS3 as best as possible, not the opposite because right now and without any effort GT6 already runs on the PC (we have seen footage of GT5 and GT6 running flawlessly on PCs already) and there's not that much of a biggie if the game doesn't run well on older hardware, due to that different PC games have different hardware requirements.
In the end the reason why lots of "ports" of console games to the PC run so badly is that the companies behind them put very little effort into the PC release, because in the current market the AAA multi platform releases sell way more on consoles than on the PC, making this just an afterthought. What I mean is that situation is not because of a technical reason, such as PC ports being harder to make than console ports or some infrastructure matter, but because of sales really.
Then what happens is consumers complain about the poor PC release and the company fixes it with patches made within a month, that solve lots of the issues, focus into better supporting the PC inputs (not a problem in the GT series) and adding more options.
At the same time, PD has been struggling for 10 years and to this day about running the GT series on the PS3, that because of technical, infrastructure reasons.
To put an irrefutable example, we know GT6 doesn't run that well on the PS3, no matter how much effort PD has put in all these years. For instance the main reason why sounds are so bad is the console. However, the times PD has shown GT5 and GT6 running on a PC the game runs way better than it does on the PS3, that including most likely that internal PC release took them way, way, way, way less effort to be compiled.
Secondly as others already said, yes it was a pain in the ass to make games run on the PS3 but that is already changed for the PS4, which is said to be so easy companies develop their multi platform games with the intent to run on for the PS4 first and then for Microsoft's own console.
Thirdly, PC games always are exploited to the fullest, because there's no hardware limitation. Me and others have talked many times about it but will repeat it again: consoles have finite resources by design, so there's always compromises and console releases are never as good as they could have been.
On GT6 you are limited to 16 players online, that with with the console struggling a lot to do so and with lots of limitations put by PD in order to achieve those 16, such as worse sound than it could have been, the physics are different online for this reason (remember what happened with GT5?), huge hit in fps, etc. etc. On the other hand, on the PC if you have a good one on iRacing you can run a full NASCAR grid and without any compromise made nor performance hit.
Yeah, they had best make some DRASTIC course corrections!
Sony still has several billions in savings and is a household name. It's one of those companies that its brand value makes it too big to entirely fail and even in the case it does it will be bought by someone else, so it will continue to exist. Sony will not go (properly) bankrupt in our life spans; as in just disappearing.
To put it in perspective when it comes to the videogames industry, Sony is so big that at the beginning of the PS3 era they lost $300 per console in order to place the Blu-ray on the consumer market, plus remember the PS2 did the exact same with the DVD 15 years ago. Yep, that big.
Also remember Sony made absurd profits during the PS1 and PS2 eras and that this generation (PS4) will likely be "won" by Sony, making a console that isn't making them bleed money.
However lets put ourselves in the desperation scenario you and others suggest:
1) The GT series selling for other consoles has practically 0 effect on saving Sony as a whole.
2) Heck even selling the GT series to someone else still is nothing in the big picture.
3) Even if Sony goes bankrupt (in reality being sold as a whole to someone else) selling the GT series separately would be a big hit to Sony's brand value, so most likely they won't be. What I want to say on this point is that the GT series will always, always be of Sony's property, no matter what happens in the future.
4) If the Playstation dies then the GT series as you know it will die with it, because PD requires way too much money to make proper GT games (huge AAA games) for what they can sell on the PC (sells of PC racing games are nothing when compared to consoles), on Microsoft's consoles (with added competition and likely it wouldn't be allowed to sell GT games there in first place) and on Nintendo's too (no one buys third party titles for those and what its audience only looks for unrealistic racing). The GT series sells more as a Sony exclusive than in the scenario of discounting all those sells on the Playstation while it being available for every other system.
5) Remember that Sega stopped making consoles but it didn't cease to exist. However most of its franchises died with its consoles and those that remain to this day are not even comparable to how they were, because of the said reasons in point 4. All Sega's racing franchises are dead and so are all their expensive to make games, even when they were as big names as the GT series is.
Anyway, not to be so serious I'm posting funny videos on these long (and sort of hateful) posts
. I recommend everyone to buy this, because right now it costs like $5 and is beyond amazing.
