I wonder what the development split has been between making tracks for GT7 vs making tracks for GTSport considering the nearly monthly content we've gotten is pretty insane for two years now. The tech jump between PS4 to PS5 is going to be even larger than from PS3 to PS4, PD will eventually also have to re-do the assets of current tracks for the PS5 GT.
Not necessarily. After the debacle that was early game development on the PS3 cell processor, Sony (and Microsoft) have learned their lesson. Gone are the days of console architecture being vastly different from PCs, let alone from each other (Sony PlayStation, Sega Saturn, Nintendo 64, all radically different). Today's game consoles are basically PCs, which is pretty great for everyone involved. The technology will be better obviously, but it won't break continuity with the previous generation, kinda like how you can still play and install 20 year-old games on your computer and they play fine.
In some ways, I can imagine the development of GT Sport going the same way. If they're supporting it so much even today, I don't think it's just because of the live game aspect; instead, I can see its development and budget morphing with the next game in the franchise on the PS5, whether it is an next-gen update or the next "real" Gran Turismo. So while they're working on new assets, new tracks, new cars, they no longer have to wait for the next boxed release, they don't even need to re-do as many assets (again, because the next architecture is very similar to the current one). They can just release them as they see fit, pleasing their fanbase. And when the PS5 comes, a brand new game on a brand new console, then the marketing budget kicks into gear.
But then, what the **** do I know?