In a few years people will be using HTML5 video, and fall back to flash where not available. A few more years after that, maybe things will be different.
The flash audience will be second class citizens. But with users needing only to change their browsers for a better experience, I think they will do so surprisingly quickly.
Like Mircosoft tried to with with ActiveX? I don't think so...
Yeah. Native code in a browser without the security implications.
HTML5 may replace it for video purposes but that's only one (recent) thing that Flash is used for. If you have an iPhone 3GS right now, Apple will have long stopped providing updates before HTML has supplanted Flash for all things. Hell, HTML5 isn't even a standard yet.