Is free art harder to make?

I think, free art is
a) hard(er) to use &
b) hard(er) to alter.

Let's say, some game developer needs a character. He would find a few ones on OGA, but the questions coming up might be:
How often have they used before in other projects? How well-known are they, how "lame" would it be to use them?

So I think, free art should be as moddable as possible. Having access to the sources (aka blend & xcf or respective formats) is just a step to rate the "moddability" of a piece of art, but doesnt grant it itself. Someone with more knowledge might correct me, but I think, with most 3D stuff you can do only very minor tweaks - if you want to avoid a complete retexturing/rerigging. About 2D stuff I have only very little clue, but it seems to me that you can alter the colors maybe, but for all others aspects, it is like: Use it as is, or take it as inspiration for a start-from-scratch.

One way to solve this is to offer half-done things, where someone has to put additional own work into the model to make it usable, but will also, as kind of side-effect, individualize it.
Another way might be the development/usage of "generators", like makehuman.org, as a generator of human meshes. I would like to make a little inspirative list here, but I am heavily lacking of examples.

Maybe it is too easy to pass the buck to the artist's side by saying "Your art is nice, but its not unique enough for me, because it is free". Also one might argue, that almost every good actor appears in several movies. You can even say, the better an actor is, the longer is the list of movies he participated in (with numerous exceptions in B-movie genre, of course). So why shouldn't good models be used in several games then?

I'm starting to forget what I wanted to point out, so maybe it's time to stop here ;)