There are numerous projects which have attempted to create this.
https://sandstorm.io/ was the biggest one but as far as I can tell its largely unmaintained and most of the apps are outdated
https://yunohost.org/ probably has the best "just works" experience but I didn't like that it wasn't using any kind of containerization which has caused them issues with shared libraries like PHP being difficult to update. As well as security concerns about one insecure app giving access to the whole server.
Ultimately the problem is just extremely difficult / high maintenance. And no one wants to pay for this work.
https://sandstorm.io/ was the biggest one but as far as I can tell its largely unmaintained and most of the apps are outdated
https://yunohost.org/ probably has the best "just works" experience but I didn't like that it wasn't using any kind of containerization which has caused them issues with shared libraries like PHP being difficult to update. As well as security concerns about one insecure app giving access to the whole server.
Ultimately the problem is just extremely difficult / high maintenance. And no one wants to pay for this work.