Just to chime in here, it only takes a single person to buy a bass, so you should at the very least try selling it for a while before you do anything with it to enhance (or not) it's sellability. You might be surprised how many folks here play fretless, even some like me who only play fretless.
Also worth noting that you will almost certainly not regain the costs of a refret in a sale. It's going to take the luthier longer to refret a fretless neck than a fretted neck (i.e. higher cost), even if it were once fretted as is the case with yours.