A priori, I'd say any enlisted/NCO would prefer being an officer (if they didn't have to work for it, etc.).

There are lots of things people might prefer if they didn't have to work for them. :)

(in contrast to Chief Master Sergeants, about whom we might ask why they are not officers.)

Because they're at the top of their career, so why should they give that up to be at the bottom of a new career? This, I have read, is what some of them would say.

Of course, that begs the question of why there are two ladders, but given that there are, it seems a reasonable response.