I think paying yourself if it does not "get to market" would be unethical, but not if it does.
I think a person (not you at all) who shams this to get a salary and really has no real intent of getting it finished is a crook.
A person who takes a piece but delivers is not. IMHO.
i don't completely disagree, but i do think people, like oam, who are making an obviously honest effort at getting to market are fair to take a pay, even if it ultimately doesn't make it to market. if it's a business, then payroll for development is normal cost and nothing unethical about it. businesses try and fail all the time to make something to market, and payroll is part and parcel to their development, failing or not. if it's hobby funding, then that's more grey area. but, imo, oam's showed enough effort to suggested he's strongly trying to make it a marketable product, and i'd have little issues with him taking a % of any contribution i'd made as compensation for his time and effort.
also, from experience in dealing with startups a decent amount, if he's genuinely trying to make market, but fails, he'll most likely have eaten far more costs personally sunk into the business than anything he might have taken back out. if it fails, it'll likely be a net negative for him personally regardless if he takes a payroll cut or not.
ask drew about this site. it's marketable and he's trying his damnedest. i don't know for sure, but i doubt he's taken anything home from it. yet, anyway. but even if he'd done so at close to 100% (unfeasible), i'd be willing to wager he's sunk way more into it personally than he'd have gotten back out of it so far. that's also not taking into account his time and expertise in setting it up in the first place, which has tremendous value in itself. it's a hobby for him as well, but also a potentially lucrative business venture. i'm hoping he's taking some home soon. same with oam.