Meh, Apple might be a little ahead of others, but all mainstream OSes and stores are basically headed this direction already. It’s just part modern security, part quality control, and part family & work friendliness. Most people on both sides actually want a walled garden. There will probably always be ways to run unsigned code and to get content that’s not approved by an app store, but maybe it’s fine if it’s ‘harder’ and not the default.
Yeah Windows does the same thing. It's something indie game devs run into. If you release on Steam, Steam launches your game. Otherwise you have to pay a certificate authority to sign your game or Windows Smart Screen will do the same "this code is sketchy. Are you really really really sure you want to run it?" thing MacOS does for non-notarized apps.
