Well, yes not everyone can afford items like that at first, but that's kind of the point. xD Not everything should be easy and free in this game; otherwise nothing would be a challenge. Everyone has the ability to save up for themselves without spending any real money at all, and I think that's fine.
Also, it would be pretty unfair to the people who have spent hundreds of millions on name changes to suddenly make them free. :p
(FBCs are purchased with CP also, which can be bought with real money, therefore giving money to the site. Without people spending real money on Res, there would be no more Res. We need to bring income somehow.)
Creatu names are a very big part of the Rescreatu economy and pretty unique to this site; most other petsites don't have a limit on names like we do, and even when they do they don't seem to be a big deal or worth any money. It's a really interesting facet of this site if you ask me. Rescreatu also isn't trying to imitate life in any way so there's no reason that the ability to have multiple of the same pet name has to reflect the real world.