I'm sure he'd have plenty of offers if he was going to sell it. As long as it really requires a decade of work to produce, somebody might value it at the labor

I'm sure he'd have plenty of offers if he was going to sell it. As long as it really requires a decade of work to produce, somebody might value it at the labor cost as a kind of proof-of-work. But what if he does another copy in only few months by reusing all the part designs? Its value could be destroyed. Probably has to become famous then die so that there's no chance of the same creator flooding the market.