Why not both? I don't see how proprietary software on Linux will slow down FOSS at all, and it'll only bring more users to Linux who otherwise have to use windows for their software, so overall more FOSS users in the community
And programs like Blender have already matured to a professional level, so I'm pretty optimistic that other FOSS apps will eventually follow, too
Yeah, that's what I'm getting at, proprietary software on Linux is just a step forward towards a fully FOSS future
For the most part, there aren't many professional fields that have a good FOSS option, so in the meantime their only option is to keep using the industry standard until a good alternative matures like Blender has
At the very least, people would have the freedom to not use microsoft or apple while still working professionally in their respective industry, so that's more free overall