That future is here. All macOS desktop apps must be signed with an $99 developer certificate from Apple. All Windows apps must be signed with a $300-ish developer certificate otherwise Windows scare away 99% of users from running the installer. I can't comment for Linux but I see snapcraft.io is getting some pretty big usage numbers...
I really can't put what I want on my Android phone. I briefly read I need to 'unlock' my bootloader using some procedure which implies getting approval from Xiaomi and/or doing a factory reset of my phone which means losing everything. Seems designed to be as inconvenient as possible.