You're right about one thing, money isn't everything. As supporters of various games are finding out all the time, more money doesn't guarantee any results, in both quality and quantity. But the fact that enough people are willing to give developer money, even when they don't really have to, should count as very good moral support. And it should be stronger than criticism from pirates who don't pay anything.
Greono almost made it, he was very near the goal he originally set for working on the game full time. And that was even though he had a lot to improve quality wise. But you could see that he was trying, releasing updates from time to time, moving with the story, etc. There was some criticism, but it wasn't too bad.
All he needed was to continue with what he was doing, maybe improve quality control a little (it would have been enough to get someone who would test the game before releasing it to public, to avoid everyone immediatelly hitting same obvious bugs; he could easily find volunteers here, who would do it for free). If he had done that, by now he'd be rolling in money and have small army of loyal followers. Instead he decided to improve the game to death. Include every imaginable fetish, make it a technical masterpiece, because why wait with that for some future game, when you can do it with your very first one, ... too much at once, he shot his own foot with that.
But he still could have pulled through. Some Patreon supporters are suprisingly loyal. It seems that once you get certain level of support, you can go missing for a year and you'll still keep half of them. Show some signs of life, and you have all the time you need for your work. Yes, there will be criticism, but mostly from people who don't support you, so fuck them. And even among pirates you'll always find someone who will defend you.
In short, "he gave up because we weren't nice to him" is not plausible. Especially when there's the other possible explanation regarding the real life troubles. It's probably combination of that, plus being a little lost in technical things.