On the flip side, Steve Jobs tried to make this happen for the iPad and Apple eventually gave up and built the Files app because they were trying to make it int

On the flip side, Steve Jobs tried to make this happen for the iPad and Apple eventually gave up and built the Files app because they were trying to make it into a system you could do actual work. "All data belongs to a single app" was at odds with most work tasks other than checking your email, and sending copies of data back and forth between apps with share sheets is alright if you only have to do it once, but it doesn't really scale.