a lot of FOSS software is written by individuals as hobby projects
Yeah that does give me a lot of patience with a lot of FOSS in general, though as far as I can tell that's never really applied to Matrix in particular. It was initially started by Amdocs, an Israeli communications firm, and then they gave it to a UK group that formed a company, and then crowd funded it.
I think it would be even better if companies and governments started shifting funds back to these projects when they switch from commercial to FOSS software (which is happening more recently) but most just happily pocket the savings and this will not change until a fundamental cultural shift happens
Or a legal one. If it were cheaper to enforce licenses FOSS devs would actually be able to use a separate personal/commercial license in order to actually get companies/governments to pay them, while still allowing them to be free for personal use. It's not exactly what WinRAR did (we were all breaking the TOS), but it's practically what they did. The problem is that FOSS devs don't have lawyer money, and you need lawyer money to do that