You're missing the point entirely.

You don't need to abandon a decade's worth of advances to ask that, for example, the Google IME team all get on the same page (Chinese, English, Korean and Japanese IMEs all work slightly differently and appear different) before implementing say... face unlock.

I'm a big fan of single-purpose tools, but if you tried to have EVERYTHING in your life a single purpose tool, you'd need a shopping trolly to carry it all around with you.