For context since success is slippery I’d take it as able to recoup development costs and provide a runway for the next project otherwise being a professional game developer could not be sustainable. This is also the worst place to be in as a developer where each project has to recoup it’s very precarious.

Both are rated Very Positive on Steam so clearly both are good games in the opinion of the gaming population at large.

The thesis that all you need to find success is a good game is clearly not sufficient.

FWIW I think Regions of Ruin was most definitely a commercial success and that estimated revenue figure is probably very low for the review count they have.