People work on it. People are getting closer to having it. Matthew Shoffner came up with an interesting approach, a very practical one. He didn't train his strength using one arm handstand push-up specific progressions. He trained it using weights (dumbbell presses). Once he got enough, or close to enough strength, he practiced negatives. This guy just went for it. In two months, he progressed to this:
It might not be perfect, since he doesn't lift his entire body completely... But he's getting close. Really close. Watch this guy.