I was talking about this just a couple weeks ago with some friends @lupyuen , I know that many people will be against it, but one of the things that are keeping developers away from developing for Linux, I think* that is they do not see the gain in doing it.. The average Linux user expects apps to be free, but if this keeps people from releasing apps on Linux, then I prefer to have the option to buy those apps.. As I already do with various of them.
Personally, I am happy that some applications from Blackmagic, Foundry, NeatVideo, SideFX, Unreal Engine and others are available on Linux upon license acquisition. They generally use RLM license software, which is quite expensive and requires some work...
The fact they might open the possibility to sell software to everybody on flathub, is a bless for me... even better if a small donation is sent to FOSS software used to make that very sell, possible. Look at the Blender Market, when you buy certain plugins, you also donate to the Blender Foundation and this helps a lot!