The best way for Adobe to save Flash is by killing it

Open != free.

Lack of openness: a browser plugin that is less stable and slower on Mac and Linux that noone else can fix except Adobe...and only if they choose to do so.

Lack of openness: a browser plugin that doesn't properly utilize cookies on non-IE browsers that noone else can fix except Adobe...and only if they choose to do so.

Lack of openness: a browser plugin that doesn't properly return HTTP status codes on OS X that noone else can fix except Adobe...and only if they choose to do so.

I think some people are forgetting that Flash is used for more than just serving up video and pop-under ads (though admittedly that would be its largest use).

There are a lot of games that may not be possible to run on an HTML 5 canvas.

Also, lost in this discussion is the fact that one of the more popular browsers doesn't support HTML 5 in its current version or possibly even its next.

Does streaming video work under HTML 5 specs? If not, that's another thing that Flash can do, which you can't with html5.

"We're going to have HTML5 for the next twenty years..."

Everybody's going to get up to speed with implementation of HTML5 and then ... stop? The story of HTML5 so far has been a mix of browsers chasing/leading the standards. In other words, the standards and the browsers are evolving together rapidly. I don't see why that would stop anytime soon. Certainly all this innovation won't ground to a halt when HTML5 submits their final release to the W3C (or whatever the next "formal" step is at this point).

Will there be some instance of an installed browser today that will still be running on a machine somewhere in 20 years? Well, probably... but remember that guy a couple of years ago that still had a CP/M system running his business? He wasn't holding anybody back.

And once everybody's on modern, standards-compliant browsers (and thus there's less friction for upgrading, i.e. there's no more "all our corporate apps only run in IE6"), I expect far more people will upgrade far more often. The web is at a really, really exciting time if you ask me.

So: non-Flash web technologies can reliably handle some percentage of Flash use cases today. Certainly more than a couple of years ago, and that appears to be about to go up again a lot more as HTML5 sweeps across the web. The number of use cases that require Flash are going to continue to get smaller and smaller over time. When will Flash be utterly irrelevant to the average user? I don't know. But WAY less than 20 years from now.

Keep in mind that they don't keep progressing linearly forever because of the nature of the service that's attempting to be provided -- neither are far off from being able to do basically all the things that can be done on a 2D panel attached to a speaker or two: interface device input, 2D/3D animation, sound effects/music, a bit of local persistence, access to the videocamera,... what else is there? I'm not sure of each's multitouch API, if any, but, really, there's not that much more beyond those things that HAS to be implemented for the vast majority of web pages and apps to fully function. Support for accelerometers and other such devices would be nice, but is hardly important to reading the New York Times or the other 99.999% of things people do/want to do with the web. Perhaps in 2030 there'll be argument about whether the web- or proprietary-way has the best support for holographic 3D displays or 360-channel surround sound, etc., but those and many other things that the two technologies don't support today seem likely to continue to overall be niche things. In other words, things whose proper role is a plug-in, not a vital part of many pages' experience. That's fine: there's going to be a role for plug-ins for a long, long time, perhaps forever. But, the fundamentals? We're getting pretty close to having them covered.

Also, I think it's well worth taking a good look at HTML5's rate of progress over the years. A huge chunk of the HTML5 effort has been toward just standardizing the response to the tag soup that is out there. That work is essentially done and doesn't have to be repeated. Just in the last year or two have things really taken off as far as adding new functionality to browsers and example pages, and it's only been in the last couple of months that a few actual commercial pages have started to use these things. In large part, that's because the web has been stuck for most of a decade because of IE stagnation. [Also note that the rest of the browser/platform vendors didn't seem to have a good mechanism to rapidly innovate together on until the HTML5 effort came together. I don't expect that that diplomatic work will have to be done again, either.] The web platform after the IE stagnation seems likely to move much faster toward covering the gaps that remain in the web platform.

I think your comments here are off base.

The SWF standards (and associated standards like RTMP) are available for free on the Adobe website. You are permitted to construct alternative implementations based on this specification. I think it meets the definition of an open standard.

Would HTML not be an open standard if the only browser we had was IE, and it was horribly buggy? No - the quality of the available implementations is irrelevant to a standards "openness".