To me dog shows are a bit of red herring or scapegoat if you will for the ruination of dog breeds. The real culprit, quite simply, is purebreeding. Whether it's for show or not is irrelevant, actually the dog show world probably aids in keeping things a little under control. The bullnastiff with its long show history is at least in much better shape than its close cousin- the boerboel. The latter isn't bred for shows so much as just bred pure to be a boerboel worth a lot of money and looking like some kind of cartoonishly jacked freak. I guess another good example is amstaff vs American bully. Yes the amstaff is 2nd rate compared to a proper apbt, but it's no where near as bad as an American bully.
The problem is breeding a dog because it IS something, rather than because it does something.
On a side note- count me in for missing the good old days. We need to bring back proper dog talk. This is a great site, just needs more traffic from more ppl, not sure what the solution is.