I don't have this problem. I don't expect perfection. Like it was stated earlier, these are still considered by many people to be toys.
Some people would look at those $100+ FM or DM diecasts and find errors.
As far as the cost,when I started building,like a lot of you,kits were $1.50 or so. About an hour's pay back then. Now they're $20 - $25. A lot of people (not me ,lol) make that an hour.
I guess all you can do is let the model makers know you're unhappy with their product,otherwise they will keep making them. We could go back to the days before injection molding- a block of wood and 4 wheels. My .02.