What do you do? You pay for support, plausibly via a crowdfunding-like mechanism - continued development and maintenance being something that's encompassed by "paid support", of course. What do you do when interest in a piece of proprietary software wanes and the original developer goes out of business altogether? Never mind, you answered that quite nicely already!

FLOSS is more viable than non-FLOSS in the long run. And we have solid empirical evidence of that, because we still have code from the 1970s and 1980s chugging along nicely as part of our modern Linux distributions. Try that with Windows 10, or even mac OS!

And yet, in the meantime...

> ... How many fewer employees do they [Blender Foundation] have than a company like Autodesk or Maxon?

...how is that supposed to be a bad thing, exactly? It's a lot like measuring the worth of a software project by the LOC of its source code, given a constant or even shrinking set of features.