that's a possibility, i can't deny that. but FSOs are parts basses to begin with, so what we're really doing is reimagining the instrument with only ourselves in mind. to wit, i have no special skills with woods or tools (i can solder!), but my first ax, from nothing but the various parts i picked for it, was a real success (the "blonde P-bass"). i got lucky with the neck (it's a great one for my hands). the rest of the parts fit. the only hitch was "the looks" --- what did i want it to look like (i.e., what was i willing to settle for)? answer: i had a pickguard custom made, that defined "the look."
if the first neck had been a fail, i would have tried another one, and another, until i found a neck i liked. that said, i'm choosing necks based on my preferences and the specs advertised, so as long as they match up i'm at least in the ball park. and FWIW, i think fretless necks are easier to deal with than fretted ones, so there's that.