While I have had this happen, it's been by far the lesser occurance for me... usually one of two things happens:
1: My car just cannot compete with the fastest car in the race. I may be able to battle my way to 2nd or 3rd, but the leaders have split off into the distance so far I cannot even attempt to catch a draft let alone catch up. And for some reason when the AI is out in front it seems to be FASTER.
2: My car is too powerful. I battle my way to the front pretty early, overtake the 1st place guy and from then on the AI seems to loose it's gusto and falls way back.
The problem is it's very hard to get a car that makes you competitive without giving you an unbeatable edge, and while it certainly can be done, it ultimately takes a long time and costs a lot to tinker until you have achieved it. Almost always I will give a race a few goes, realize I can't catch the first place guy without beating my way to the front of the pack off the line and blocking him the whole race (if even that) then I go add a few upgrades and now I am pulling away from him no problem
This is compounded by the fact that you are rarely ever racing more than 1 or 2 cars. The rest of the pack is just rolling roadblocks to get past before you fight for first, and since you need to pass them all AND beat first, your car is going to be so overpowered for the rest of the pack it's not a race with them, it's just making sure you don't do something stupid and collide with them and spin out or get pitted.
Further more quite often if you haven't gotten up and started battling with for first by the second lap, you will not catch first unless you are way overpowered. Again this has something to do with the AI being faster apparently when in the lead.
So I can't even enjoy a 5 lap race, moving up a few positions each lap cleanly, I have to power through the competition and be up fighting first by lap 3 or else all is pretty much lost if I have a reasonable car, if I have an overpowered car then again there was no challenege to begin with.
While I don't like rubberbanding or boosting, it seems to me two obvious solutions are:
Payout for less than podium finish IF your car is weak enough. ie the game ranks your cars apparently ability and if you finish above that rank, you get paid out high Cr.
and
Allow the CPU to dynamically add engine tunes based on how close your car is in spec... for instance if I just tuned my car up 40HP and now pull away from the AI in the straights, give the AI lead car a stage 1 turbo to make him a bit more competitive. This of course assumes the AI is up to snuff and upgrades like turbos and suspension actually make a difference in how they drive and don't just make them faster all the time.