You should consider that we've got a lot of free content ever since the game released so it is only natural that they need some sort of external consistent income to continue to provide extra free content, I bet that offcial licenses for tracks and cars are not cheap.
I honestly thought they would bring payed DLC's at some point and leave microtransactions out but this way is actually better in my view has long as they do not overdo in every single car price moving forward.
One thing I request, PD please bring back championships and a cash reward associated with it.