> The cross browser web already exists. It's called AS3.
AS3 is not cross-AS3-player.
Does it have two (or more) interoperable implementations? Can it run on platforms not supported by Adobe?
While single-vendor closed-source plugin is strictly speaking cross-browser, it doesn't have things we want from "cross-browser" solutions:
• freedom to run it on any computing platform (people run HTML+JS on their Amigas, because they can!), now and in the future (what if Adobe decides that maintenance of Flash Player is unprofitable? How useful would be archive.org in 20 years when none of supported platforms is alive?)
• competition between implementations, so that if one stars sucking or does something user-hostile, competitors will take over (You don't have browsers with hidden hard-to-delete cross-site cookies — they compete on privacy features!)
> You cannot build a 3d racing game in HTML5+JS in the browser.
You're misappropriating the term 'cross-browser'.
It does not mean open-source or open.
It means the technology will run across most browsers.
And Flash does that.
You have some valid points but none of them seem to refute the idea that Flash isn't cross-platform.
Does Firefox's IETab make ActiveX cross-browser? It runs in more than one browser chrome! …except it relies on one-vendor's binaries and is limited to platforms supported by the vendor — just like Flash.
Even something that is "cross-browser" can have all negative aspects of a single-browser solution.
My point is that for HTML cross-browser is not the goal in itself, it's only a way to ensure that technology is freely implementable by anybody, that content doesn't rely on bugs in one implementation, that fully-functional implementations can be available 10 and 100 years from now if necessary.
AS3 is not cross-AS3-player.
Does it have two (or more) interoperable implementations? Can it run on platforms not supported by Adobe?
While single-vendor closed-source plugin is strictly speaking cross-browser, it doesn't have things we want from "cross-browser" solutions:
• freedom to run it on any computing platform (people run HTML+JS on their Amigas, because they can!), now and in the future (what if Adobe decides that maintenance of Flash Player is unprofitable? How useful would be archive.org in 20 years when none of supported platforms is alive?)
• competition between implementations, so that if one stars sucking or does something user-hostile, competitors will take over (You don't have browsers with hidden hard-to-delete cross-site cookies — they compete on privacy features!)
> You cannot build a 3d racing game in HTML5+JS in the browser.
There's a quite convincing proof of concept that you can: http://helloracer.com/webgl/
It doesn't work on iPhone and I'm not sure if it works 64-bit Linux, but that's not a problem, right? :)