Polyphony is pretty greedy with their microtransactions, so I imagine they wouldn't be quick to pay their creators much. I've never paid for in-game currency for GT7, but that also means that there are many cars that I will never obtain. I've played 70+ hours and have never had more than $3 million at once. There are dozens of cars that cost upwards of $20 million.
You're right though, it's nearly an impossible feat to ever create something from scratch that even comes close to comparing to GT7. They just have way too much money and experience to really compete with, at least for now. The way they see it, they're already making great money so no need to innovate. Once it becomes clear they will be able to bank even more, then that's when some of these new ideas will start to come to life Who knows, will probably be many years down the road. It's fun to fantasize about it though. I look forward to our youth's potential future. There will be even more opportunities than there is in 2023.
Someone would have to come along, offering a better deal to consumers, snatching their market, then they'd decide to "innovate".
I do enjoy thinking about it. I think that's what keeps me grounded in reality rather than throwing my money at every little thing that says it'll do something, eventually.