Do you leave your PC with the stock programs on it or do you find the programs that suit you best?
You're trying to make a comparison where none exists. Of course I install applications I need. I install applications I need on a smart device.
What you're talking about would be akin to me saying, "you know, the windows start menu is shit, I'm going to download a bunch of start menu replacements until I find the one I like."
A keyboard is simply a vital system component. It's not an "app". I shouldn't have to spend any time at all trying to find a replacement for it. It should just work and be usable for the ultra vast majority of people.
Of course, we're going to disagree on the ridicilousness of switching out keyboards, and that's ok. That's why there's Android and thats why theres iOS/Wińoes Phone. So we can both try to find ways to make ourselves happy.