HTML5 is cool but it's not the end-all. You have a whole set of new issues to deal with when you use HTML5. You have to worry about cross-browser compatibility and specific rendering bugs, whereas Flash authors don't. You have to rely on the slow JavaScript VMs included in even the fastest browsers (even the "fast" JS VMs are still rather slow), and then you have IE, which is still used by > 50% of internet users, of which much is IE 6 or 7, which are outdated and _extremely_ slow. You have audio synchronization issues. There is no ready-made IDE like Adobe's Flash IDE, meaning HTML5 development is much harder for many people. There are other issues too.
The fact is that HTML5 is not a reasonable general replacement for Flash. If you want your thing to work for most people, you are going to have to write in Flash anyway. Realistically, only a relative handful of people could run a HTML5/JavaScript program at Flash-equivalent speeds. And that assumes that you just want something in Flash that HTML5 could do; there's still RTMP and significant swaths of other stuff that Flash does and HTML5 doesn't.
This doesn't answer the question of why Adobe doesn't do that, it lists the things that Adobe could step up to do. Yes, we know there is no ready-made IDE like Adobe's Flash IDE: fixing this problem is something Adobe can do, by providing a ready made HTML5 IDE. Why isn't Adobe doing that and leading the charge? There are distinct problems with HTML5 replacing Flash, and Adobe is in a unique position to partner, consult, contract, and contribute to that. For example, if everyone else's javascript VMs are crap and Adobe's Flash interpreter (which is close to javascript, isn't it?) is awesome, then Adobe can help contribute rather than taking a beating from industry leaders (Jobs) and be part of the solution rather than be viewed as part of the problem.
I think the answer is a common one in free markets: cost.
Adobe would need to invest a _lot_ to make a good HTML5 IDE, and what would they get then? At best they'd be in the same situation as they were before just with HTML5 instead of Flash, and on top of that they would have lost control of the platform.
So the bean counters find this kind of proposition difficult to swallow. And if you say: but what if someone else did? Then they'll reply: well, then make sure Flash kills anything HTML5 related, and that's how they end up putting a lot of money to preserve the status quo, instead of using their baskets full of gold to make them run faster.
Compared to C, Java, OCaml, and so forth, perhaps.
Compared to Ruby, Python, and PHP - not so much. (take a look at the v8 entry. and this is from '09 - v8 has seen some performance improvements since then)
None of those comparisons really matter in this discussion, except Java, which is clearly out of the competition anyway. Why? Because unless you're suddenly running Ruby, Python, PHP, C or OCaml as a client-side script embedded in your browser, you're comparing apples to oranges.
It would be interesting, though, if someone could point me (and everyone else) to a reasonable, credible comparison of HTML5+JS vs. Flash vs. Silverlight.
I've been playing with Silverlight and am very well impressed.
It is much faster than Flash (my tests where the RSA encryption algorithm), has a way more comprehensive library (specially for data manipulation) and "looks" way more secure than Flash (please take this last one with a grain of salt).
Its acceptance is still lagging (I estimate something like 50%-60%), but growing fast. MS promised the new Windows 7 phone with Silverlight on it for September. It might increase acceptance.
From what I see HTML 5 adds a lot of interesting new gadgets and features (like websockets and video streaming). It is a great innovation, but is not for complex Rich Internet Applications.
I'd expect, for the next 5 years, Silverlight to become the platform of choice for RIA (mostly CRUD applications), HTML5 for video streaming and some simpler games and Flash critically sandwiched between both.
Are you insane? I've had to develop a CRUD application in Silverlight, and it was dauntingly slow in comparison to Ruby and Python frameworks, and the tooling is still behind the rest of the C# frameworks.
1) in most of your post you argue against the performance of VS2010 and how slow it is to edit XAML, not the performance of your Silverlight code/application. I take that it was as good as mine. And I think that this is what is being discussed here.
2) I agree that VS2010 is indeed much slower than previous versions, although I didn't experience something as terrible as you. But I am running it in a 3GHz quad-core with 4Gb of RAM, so...
3) Silverlight is a WEB client solution and that's the scope of this discussion and the post I answered. Correct me if I'm wrong, but I think frameworks like Django and Rails are server-side technologies and, as such, don't compare to Flash and HTML5, and are out of scope for this discussion, right?
Partially so. However much Silverlight might fill a niche for rich media, the fact is that 99% of the use cases will be for internal business applications, where it fails spectacularly. And in the case of ubiquitous media apps, it's simple: Siverlight is not nor will it ever be ubiquitous.
IMO the fact that Silverlight hasn't been canned is just another point that shows that MS doesn't get it. When they saw where HTML5 was going they should have jumped on board with both feet. It's too late to force everyone to use their OS at this point so they should have been focused on being compatible with everyone but simply running better.
Silverlight will get a bit bigger but it's never going to matter in the long term, any more than Java applets ever will.
The cynic in me thinks that MS thought that rather than spending energy to "get it" and maybe failing, they could back all horses and see who would win. They usual strategy (and Google's current m.o. sadly).
Why is java clearly out of the competition anyway?
I think this is a remnant from a time long gone, where applets were much worse than they are now. They have worse user experience than flash, but the difference isn't really that big anymore (e.g. http://www.pulpgames.net/milpa/).
AS3 is fast as the language, but developers can make too CPU intensive animations there too. Moreover AS2 in which a lot of ads are still made is awful slow. And you can't control which ads (and the quality of the implementation) will be served when you're on some site -- therefore on weaker processors most of the sites which present the flash ads are amazingly hard to use -- you just experience lockups all the time.
The fact is that HTML5 is not a reasonable general replacement for Flash. If you want your thing to work for most people, you are going to have to write in Flash anyway. Realistically, only a relative handful of people could run a HTML5/JavaScript program at Flash-equivalent speeds. And that assumes that you just want something in Flash that HTML5 could do; there's still RTMP and significant swaths of other stuff that Flash does and HTML5 doesn't.