Before City of Heroes went free-to-play, I would have agreed with you. The problem now is that everyone and their mother can create an account, potentially fill it up with 1,000 characters, take a lot of valuable names, and then disappear.
I've already come across four different triple-boxers. People running three accounts simultaneously. That's the potential for three thousand names.
Given enough time, it's going to get to the point where the only available character names are B0b12x34.
On the flip side, there's no way of knowing what's going on in a person's life that prohibits them from logging in.