I have a similar tendency to get caught up in side shows, but assuming the real estate market is reasonably healthy where you are once the building is done it is an asset that you could liquidate if you wanted and that should net you more than what you put into it.

But if the market is not healthy then liquidation is not an option but you can turn it into an income generating asset. The hard part will be to rent it out to people that want to have living space whilst still having access to part of it as a workshop, such a mix tends to be quite bad (I lived like that for a couple of years but would not recommend it to others, unless your work is your life it's going to be frustrating).

Regardless of the outcome: you have created something that is absolutely off the scale for a single individual, and that's something to be proud of, your stamina and ability to stay focus during all of that time is proof that you are capable of incredible feats and the experience will serve you for decades to come in whatever enterprise you care to attach your name to. Your biggest challenge will be to choose between several options, (1) cash out, then continue to chase your dream, (2) become a landlord and use the surplus to live off and regroup (assuming the maintenance of the building doesn't eat up your time) and (3) find like minded individuals and treat the building as a shared resource (so allow them to buy in to liquidate some but not all of your capital and end up with shared responsibilities and labor). If it works 3 would be lots of fun, but it will require very careful selection of the parties that you allow to buy in. 2 will be less fun, especially if the building still eats a lot of your time but it may turn into a stable source of income. 1 would allow for a clean break at a (hopefully) slightly higher level than where you were several years ago, and with extra cash and more experience your chances of success for your other project have gone up.

There may be other options as well that I haven't thought of, and given that I don't know anything about the location where you reside (which is the main factor in real estate pricing) it may be a case of throwing good money after bad. But the experience is yours, regardless of the outcome and that is an investment in yourself. Those will pay off, even if not immediately.

Much, much good luck with all this, if you want to use me as a soundboard you're more than welcome to email me (mail in profile).