Well, I guess you must be the lucky one because, I am not lying here, I have had 30 or 40 roulette wheels and I have been able to correctly guess where the wheel would stop every time. And every time it has always been the lowest amount of money. This is completely at odds with, say, the similar system in Forza Horizon 4 and 5 which does feel fairer. Statistically, I should have won at least one car by now in GT7 but I haven't, not any a car part! 10,000 or 5,000 credits are the most I have won.
Whatever algorithm Polyphony Digital are using is one that, in my opinion, gives extremely low odds but that perhaps ties in with the microtransactions so the game pushes the player towards spending money? Gambling mechanics really should have no place in *any* £60+ game in my view and I would rather have just won a fixed amount or a specific vehicle. I do not understand how developers can think random gifts/loot boxes are entertaining or fun.