Well, I would say it will be quite a while for android to be surpassed. Each iteration keeps improving. Lollipop is pretty good. M has some nice new features. I'd say they might not run out of steam until they get up to the letters Y or Z. But only cause every OS has copied each other to the point you can't tell them apart that much anyways. So... what does google do after they reach the letter Z? Does the world end? Dave999, I see countdown potential here!)