Yeah righty, that’s like trying to stop the ocean with your hands. You know that 99.999% of users will have several applications or gadgets forcing them — and eventually you, if you want to remain socially functional — to install an unrestricted alt-store.
Eg: anecdote: mother-on-law was gifted a cheap smartwatch (Samsung I think). Installing its companion software required downloading and registering to a whole new store on her Android smartphone. Weirdly enough I think it was also a Samsung, already had 2 stores (the Samsung and Play ones), yet she (we) had to dump yet another one on that sorry mess.
E.g. imagine Google rolling their own Play to install Chrome or Maps. Facebook for Whatsapp, Amazon for Kindle et Al, Netflix for its own… etc etc.
No the moment that happens it’s over