I think i've realised what one of my major issues with this game is that's been just out of reach in my mind for a while.
The focus of this game is not really the racing itself - its about making the numbers around the racing go up. Each singleplayer event is an un-connected one off race that is important only in the broader context of how much your overall level, each discipline-specific number and your cash balance goes up by at the end and/or what you'll get from the next wheelspin, how many skill points you got to unlock skills for your car.
This is further exacerbated by a linear relationship between time and payout - longer events pay out more money. However this relationship doesn't change as you grow into bigger, faster and more expensive cars. Going back to the game which probably popularised the car collectathon sub-genre, Gran Turismo, in particularly GT3; Ignoring the championship payouts,
the single event races don't get much longer but the payouts increase as you progress. For example, the first races in the Sunday Cip pay out 1000 for a 2-lap race but events later on like the Race of NA Sports pay out 5000 for a 2 lap race. This escalation of prizes with costs is better at keeping you in the sweet spot of focusing on the actual racing than where i often found myself which was planning how to maximise skillpoint grind to exploit the nissan fairlady cash doubling process for a measly 150k in the face of cars costing 10 million.
I was lucky enough to pull both the cash and xp-boosting forza edition Alfa Romeos out of wheelspins, but given the above the game may as well only have those two cars in it because they are the absolutely optimal choices for levelling or getting money faster to afford the really expensive cars or houses, outside the will of the wheelspin gods when they aren't showering you with patterned slip-on shoes and dabbing emotes. Any race NOT using either of them is a waste of optimal xp or cash, especially if you haven't grinded the skill points to activate the additional boost perks within their skill trees beforehand.
I'm trying to avoid being too tinfoil hat about this as I know it can cause consternation, but all these issues could be "solved" with spending real money on car tokens as a shortcut currency or buying wheelspins to brute force through either the car or money bottleneck. Given the fairly quick about-face with FM7's plans presumably well after Horizon 4 was in development, it wouldn't surprise me if such options were going to be there but were yanked after all the battlefront hullabaloo.