Flash may very well be on the way out as a browser plug-in (a distribution platform, if you like).
It will likely live on a long time as an artists' tool.
Flash as a platform, a plug-in, was a way to solve the problem of "I've made this cool animation in Flash, now how do I show it to people?"
Adobe has gotten with the times, and turned Flash into a vector animation tool with the level of features for professionals you'd expect (think Photoshop or Illustrator). Sure you can make a "Flash movie", but you can also import your artwork from better creation tools, easily animate it with tweens (etc) in Flash, then export to any number of video or animation formats, or more importantly to frames or sprite sheets. Those exported formats find their way into your game, program, etc. The old "Flash movie" has nothing to do with this workflow.
The plug-in is decreasingly useful every day. The tool is quite useful for the designer/artist and will live on. You just won't watch Flash-created content in a Flash platform plugin. You'll be watching Flash-animated content (likely created outside Flash) in some other platform and never know Flash was part of the picture.
You don't look at graphics in a Photoshop or GIMP plugin, or play iOS games inside XCode, but the tools still exist and are useful, separate from the obsolescence of the delivery platform.