To be fair T10 has significantly more employee numbers than PD (tiny for a first-brand company)
T10 has grown exponentially. And they do deliver a lot of content. PD, owned by Sony Computer Entertainment and active since 1997, haven't delivered many features/cars compared to T10 (the infinite wishlists on gtplanet, for example, are a good indicator of what is missing...gt after gt, year after year after year). Always with the same excuse of "the future". Always fixated with esports. But not everyone cares about esports. Not everyone will be doing endurance races, not everyone will compete in official events and not everyone will be using a steering wheel. Pretty far from "everyone", actually.
Also for the games being made more fun, Forza is less realistic than GT, practically a simcade (though GT is still in this category too, but it's the one that is closer to hardcore sims). Horizon is also an entirely different game as it's free roam/open world
It's all about opinions, you want a more realistic feel, you have GT. I want a more all-around fun game especially online, I'll stick with Forza Motorsport, even though I will fire up GT7 from time to time. Because traditions.
I am personally not interested in realism online if you're only letting me drive in the same 5-10 cars over and over and over again, especially with the bad triggers of the DS4, no real tuning, no setups to save in specific files, and no real promise to deliver (with GT7) at least the same amount of features/cars offered by Forza Motorsport on last gen.
The triggers on DS5? As of now we do not know if they will be any good with GT7.
I know about the xone controller with FM 5-6-7 and of course it makes you feel when you start losing traction, so you can make adjustments immediately. I am only hopeful for what will come. It can't get any worse, it will only get better.
Anyway, we claim GT to be more realistic, yet we don't have extensive tuning, no real time telemetry in practice mode to make adjustments without quitting a single session, no clutch button on the controller, no breakable barriers instead of invisible barriers in rally stages. Among other things.
Other things that grind my gears are the awful economy system that won't allow you to get 20mil cars even after months of racing and saving (I know I did, I have a busy life like many other players), and daily gifts (or should I call it infinite list of useless duplicates in my garage that I can't even resell)