I was in the market for a dive light. My instructor recommended a particular brand, I was looking at another light not because it was good but because it was cheap. His comment was I could buy a cheap light now and then another one later when that one broke, or go ahead and just buy the better one for just a little more up front. It would be cheaper in the long one to get one good flashlight than the cost of two cheap ones. Penny wise and pound foolish.
The problem I have with this part of your post is that often-times that simply isn't true about the cheap(er) equipment. It certainly isn't true about regulators, BCs, masks, fins, or tanks. In fact, lights might be one of the few pieces of gear that prediction could actually hold water (no pun intended).