He wasn't proven 'right' as much as 'successful'. He wanted to keep flash off the iPhone and iPad and he succeeded. Just because Adobe, faced with a ban on the most important mobile platform, decided mobile flash wasn't worth the development effort doesn't mean that they couldn't have created a viable player on iOS. With enough money and the improving hardware of devices, they almost certainly could have. But even then they'd be left with the fact that native apps are succeeding far better than web apps on mobile devices anyway.