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
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.
But in this case, Android does exist.
[0] Misunderstanding leading to misattribution: https://quoteinvestigator.com/2011/07/28/ford-faster-horse
I get that people like their iPhones. My wife is one of them. I'm not. People are different. Choice is good. Some folks choose to cede control in favor of simplicity. Go off.
-makers- want other app stores, but I'm not sure consumers do.
I'd go so far as to argue that -consumers- like the single-app-store, and see that as a feature.