I understand this isn't really comprehensive, but money wise, 2 people spent about 1.5 years on the apps and finally made 100k. Seems like they are just starting to get decent ROI and the battle for profitability is yet ahead.
But you are correct that it was the best ROI so far for any of our apps.
They built, learned, and re-built. They're now ahead of the game. I admire that.
I think that might be the path for most app developers to profitability--having many apps that generate steady income, rather than having a big hit.