I think the
same people would be up the front, and the
same at the back, if the rule fixed people to one car personally.
After a 10 year lay off from the sport I am completely at the other end of the competitive spectrum. For me to be more competitive at a club level requires my driving to improve, become more consistent and crash less. I could own 15 cars, but the same would hold true.
RC racing is expensive, but compared with most other forms of motorsport it is reasonable, so if you can compete at the top end of a regional / national, chances are you are sponsored anyway and getting a truck load of either half price or free stuff to help you on your journey.
So the short version of this reply is, one car or two cars, at which ever end of the pecking order you are, I don't personally think it makes much odds.
Obviously my personal opinion, no disrespect intended