Generously, we're talking about ~$100/hour, my guess is it was actually a lot less than that, maybe as low as half or a third, and this is for an idea that got some traction.
That could be a good wage for some groups of people, but my guess is you'd find a much better one either a) growing something to a larger size or b) working for someone else.
If you're really interested in building these tiny products though, then it could be a way to support yourself doing what you're interested in. I just wouldn't generalize this strategy to "this is a good way to make a living".
On the flip side, I bet doing this sort of thing really sharpens the entrepreneurs skillset - identifying good ideas, quickly bootstrapping a product, and negotiating for funding, so I bet you're getting some pretty big personal levelups as you go.