I mean anybody can do anything so the talk here is about what one person can do and is actually doing rather than the potential of what they can do.

Google I don't know if it has the potential or not but it doesn't seem to do anything to build good products it never has whatever successes it ever had.

It also creates very buggy apps. For example, even now Gmail and YouTube is buggy on common paths. For example, try deleting your spam emails and you will see the spam number on the sidebar will not clear unless you refresh. YouTube comments on the YouTube Android app often doesn't load or it loads for the wrong video etc.

So historically, Google has always been bad with actual product development. So it's not really a stretch to say that one person can do better than Google.