Well, for one, this isn't an EA product.
Secondly, this game is brand new, from the ground up. So, it's kind of to be expected a bit.
Third, this is the first time a NASCAR title will appear on this gen's consoles. So, it's really not much of a surprise.
I do agree with your sentiment though that I'd also like to see more depth etc. to it. However, for a first year title, being built from the ground up, not including the Xfinity series, or the Truck series at this point, or even a paint booth, isn't a huge deal. I'd actually think not having a paint booth is more frustrating than no trucks or xfinity at this point.
I get your point though, but to compare it to a 2009 title, that had been through several years of development at that point, to a fresh, new game built from the ground up only Since March (or May?) of 2015, it's not a huge deal I don't think. It sounds like their plan is to evolve to Xfinity and Trucks, but it's going to take some time.