@baldur Good post. This has been a flaw with FOSS for a long time. You can't build a sustainable model on pure voluntarism. FOSS is a great idea, but it either needs public funding or a model where the users pay for the development. There are a few companies that rely on FOSS and also contributes to it's development, (ie the user pays model), but way too many just treat it as free (as in beer) software.
Public funding is probably a more reliable route. It could be a variant of user pay along with the "public money, public code"-principle, but (some) software should be treated as infrastructure that needs public investment.