Out of interest, can you link to some of these people spending thousands on GT7 MTXs?
Also, if the flex is how much they've spent, all PD need to do is have expensive MTXs, they don't need to dramatically negatively affect the economy of the game. People say they want more races that pay out the same as the big 4 - okay, that's still 15-20 hours... surely a whale spending thousands isn't go to miss out on the flex in favour 15-20 hours work, especially when the trinket they get isn't required for progression, is not pay to win, and many people won't give a **** about, that's functionally inferior to assets everyone has easy access to in the game. GT is a 4 to 5 year life span game, with only a trivial number of things that are close to unobtainable... it's not like there'll be a new game every year, or massive updates you need to buy assets for every few months... there's literally no rush that requires you to spend on MTX's aside from the not-at-all-justified FOMO in the LCD (because everything comes around again).
Whales may exist, that doesn't mean they have any bearing on the economy of GT7.
If I had to guess I'd say PD priced the MTX's to give sport mode players a chance to skip the offline portion of the game and still buy a load of cars, tyres, ballast etc. for a one-time fee comparable to an iRacing subscription, without at the same time giving people an easy way to massively cheese the offline collector element of the game. That's the only way I can make sense of the pricing, personally.