Young man, bodybuilding has everything to do with progression.
However, bodybuilding is not simply powerlifting in a higher rep range, not for everyone.
Bodybuilding for most people has to do with strength gain in a moderate rep range on SELECTED movements (SELECTED may not be flat BB bench, it MAY be smith wide to neck for you..). If you bench even three plates (hell even TWO) for reps and have poor chest development, chances are you need to use a different set of movements rather than just mindlessly pound away at a single movement and use that as a yardstick for yoru progress.
Obviously, the time to start considering alternative movements is when youre out of the beginner stage and able to contract your prime movers during said movement, rank beginners would do betetr sticking with the basic moves and eating to gain size. There's no reason to "wait" till youre able to press ten plates a side before you see good development. This is as much a game of "understanding" yourself as forcing progression.
If you're in the intermediate category (sounds like you are) and still using the flat BB bench as your primary movement as a bber, it BETTER be workign for your chest development NOW. And it betetr have been working since last year and so on.Too many (natties usually) are severely deluded on this board (looking at the responses to the thread on that bbing family guy bench 6 plates a side for reps lol) and will stunt their development thanks to unwanted dogma.