I'm in no way advocating that money grows on trees, or that people should play the game the way I choose to do so. I've done a complete 180 from how I played GTS; which consisted of me doing 95% sport mode - to which I loved every second of. All I'm eluding to, is that there are ways to play the game other than needlessly grinding for cars. Buuuuuuuuut, if you're the sort of person that needs to have all the cars right now, then yes.... you're going to have to grind, unfortunately. However, if you don't require the instant gratification of your dream garage right now, then yes.... there are many different creative ways to play the game, and more than a few "clubs" on the forum that will show you how.
As far as people being tied to a PS4 seemingly due to financial reasons, I get it. But on the other side of that same token, I have a hard time believing that had Covid not become what it did - and GT7 was released as a PS5 exclusive as planned, very few fans of the franchise would have allowed themselves to be left in the dust. They would have figured out a way to be able to afford a PS5 (assuming they are of working age). Someone correct me if I'm wrong, but I remember the outcry of GT6 on PS3, being the exact opposite in that the fans were wondering why it hadn't been released on the new generation hardware. And just like then as it was 18 months ago, it was a smart business decision by Sony at the time. However, now that supply chain issues are no longer an issue, it will be a smart business decision by Sony to start making "PS5 Exclusive" updates for all of their first party titles, forcing people into new consoles. Not to mention, that there's another completely relevant side that's seldom talked about in regards to PS5 owners and Cross-Get titles...
.... That those PS5 owners deserve to have a game that fully takes advantage of the new-get console that they spent their hard-earned money on. Especially when taking into account how long games take to develop these days. They may never get to play their favorite franchise that was optimized for their current hardware. Although to counter my own aforementioned point; I think Sony will delay PS6 by at least a year or two, because the demand for a new generation system would have been staved off for an additional 2 years because of previous supply-chain issues.
Regardless, I think it would be safe to assume that PD/Sony will start opening up the content drip as Forza's release draws nearer. They'd be dumb not too. And this is good for everyone