There's also the option of changing the length of the race, something it seems SMS should have done with PC3.
Yeah, but not many people may see or use the option, as it is hidden in one of the menus.
Even myself, and I played Forza for long, I found it out only after a while (and because I read it from a forum).
Imagine if they were designing a Career mode like that you start as a driver of an amateur Racing Garage, building up your path, but keeping an eye on finances. So for example, at the end of the race the damage you have taken needs to be repaired and costs some money.
To the point that, if you destroy your car too many times, you need to re-do the championiship at the end, and you cannot move upward in the Tiers.
Or, on the opposite side, to get the best cars you need to drive clean and save as much money as needed.
This, combined with the idea that you don't need to win at any costs. But even a fourth or fifth position (out of twenty) is a good achievement, and grants you some sponsors.
Dirt Rally 2 has already something like this in place.
All games I played in the last 10 years have such anonymous Career modes, with small and insifignicant variations to each other, and an empty of progression (race after race, but no sense of story behind).
The last truly enjoyable game with a good and immersive Career mode was Toca Race Driver for Xbox, almost 20 years ago.