Is the pool of 4 down towable vehicles diminishing??

I suspect that some vehicles where flat towing is not permitted according to the manual actually could be anyway but not sure how one would know without taking the costly gamble. I've towed a 2012 Chevy Sonic for 31/2 years and it tows great and is a great car also. They are still towable except the RS but the hook-up point is rather low. I think next I will go to Focus; a little bigger.