I think as others have said, you're mixing issues, many proprietary apps are completely free when it comes down to money, and many opensource apps ask for payment, I say many, I dont know to many, but I know they exist, I can use the example of Converstaions.
As I wrote, I have no interest in having Instagram or Snapchat for Linux. I also mentioned ethical software. So by proprietary, I only mean not open source, not GPL. My interest is in having more honest apps, more resources, more indie developers, and hopefully, more Linux phone users.
Theres also the question of, how that purchase would be carried over to your other linux distros, which use there own stores, and don't use click, for example, fluffychat is in the snap store, if the fluffychat team decided to charge, would a user have to pay twice, once for mobile and once for the snap store?
Yeah, I didn't think of that. That's a whole other can of worms.