How well did that work out? I mean, really? YouTube just completely switched from Flash, many other video sites are still pushing Flash or sometimes even Silverlight, HTML5 gaming has still yet to really take off the way Flash gaming did. All Apple did was push these interactions to native apps instead of on the web.
It's been what, 8 years since the iPhone was released, and Flash is still around. I didn't notice a huge decrease in Flash usage when Jobs made the announcement. It doesn't hurt that they have strong competition and Android can still to this day play Flash content if the user wants.