On history. Each tech is getting faster to the masses. Tv to colour tv to satellite to LCD and so on. Each tech takes shorter time to reach masses. Think of Phone to portable (carphone) to cellular to a full smartphone. Smartphones (with Apple) took just a couple of years. Now its android, who knew what Android was 3 years ago? Ipad, what was Ipad 3 years ago? The list is long. What i want to say is that tech is moving on and we are happy to use it. Search the web, there are graphs and research on this subject.
The wii was in essence an overclocked gamecube, and by looking at videos it seems the wiiu is quite close to a xbox360.
Apple as a brand is a bad example since they just copypaste other people's ideas and put a nice badge on it. Google can help, but in essence they rip off microsoft a lot and those products were available to the masses at least 5 years before (in some cases 10 or more).
Of course RAM was an issue that made PD not add lots of things to the game, but those were secondary aspects that aren't related to actual content or improving the game as a whole.
GT5 on the PS4 would have been a bit better, using models and textures on the highest quality they have at the office (running on a PC) and so on, but the core flaws would still be there anyway, including standard cars and tracks, sounds, awful menu system, etc. Just better illumination and a cherry on top of a pile of crap.
What PD didn't get is that sequels in franchises have to be released as close as possible, even more so in console games. If you want to make money there's no such a thing as reaching perfection before releasing the product, because that takes an absurd amount of time.
Lets hope they don't make that mistake again, though Forza games are released every 2 years and it's been 1 year and 10 months since GT5.