That intention would be fine if the car prices weren't so ridiculous, the credit payout so poor and the UCD being one of the most ridiculous ideas in modern game design.
If there was a clear path to getting all the cars in a reasonable time frame, one that didn't involve endless grinding and checking of the UCD, then maybe some people would take a different view on the limits.
But sadly, there is no clear path; I duped a lot of cars over 2million, and I've still got 40 standards or so to collect; unfortunately, they're all the 20m, 15m ones.
There is no reason whatsoever for such cars to be that price, and once I spend 15m on a car, I've got start saving up again for a 20m one. It's insane game design, and it's a big issue and criticism of Polyphony: they can't design a good, well-balanced game to save their lives.