I think sometimes us customizers take for granted the things that other people that aren't so artistically-inclined can't do so well (paint/sculpt/etc). From our standpoint, of course making something ourselves makes more sense than spending $100+ dollars on some sort of custom on eBay. . .but for the majority of collectors out there that have ZERO artistic ability and have no desire to attempt it. . .it makes perfect sense.
I can definitely see both sides of the argument. Yes, there are some customs (clones in particular) that sell for around $60-$70 that probably don't warrant that much based purely on the level of detail that went into the custom. But at the same time, I personally would easily pay $60-80 bucks for a clone that was done by sithfire_30 because its a QUALITY clone.
Customizers that sell their work for higher amounts of money seem to get slightly "crucified" for it because of two reasons (that I can see):
1. The customizer criticizing is CHEAP. It may not be his/her fault but I get the impression that they would not be able to justify spending high amounts of money on ANY custom irregardless of the skill or detail involved. I myself have commissioned quite a few custom items ranging from paintings to figures and have paid a "hefty" amount for them and so maybe its because of that, that i can understand when some collector pays what they pay for something that is either OOAK, or hand-made etc etc.
2. The customizer, while not agreeing with people selling customs on eBay, has for whatever personal reasons decided to put a couple up and they have gone for less than what they thought they should (of course comparing them to the customs that went for a lot but they felt did not warrant it). The truth of the matter is that sometimes a good quality custom won't sell for much because the timing is bad. . .OR there's times where a custom won't sell for much because its. . well. . .a loudy custom.
I'm not trying to ruffle any feathers but I actually started with eBay before knowing about (and joining) any of these forums so I like to think I have a decent understanding of both worlds.
Again, just thinking outloud.