Top labs are *still* researching how to replace passwords while maintaining security.
I know. I've tried my own hand on this topic, to no avail. It's really hard.
And yes, entering your password once is a very big progress.
That's true except all kinds of people have learned to use GPG.
If you have to, or really, really want to, you will learn to use the worst tool in the history of mankind. But we should think about people who have no such drive.
The real reason people rarely use it is pure laziness
That's a cop-out. Another cheap excuse. You're blaming the user and stopping there. Let me help you with some cognitive dissonance: The same users that you call "lazy" spend an hour a day clicking on a screen to plant FarmVille crops. The most useless and boring activity ever invented. If Zynga can get them to click on some pixels repeatedly, twenty times a day, why can't we get them to click on a button once?