I feel very much like the author. People think : HTML5 is the future! Yay so let's just forget everything. X is dead. Y is dead, Z sucks etc. Like the post author said people treat things as religion. It's idiotic at least. The transition must be slow and calculated. You must use the right tools for the right tasks.
Technologies like Flex, Air , Silverlight may be dying or dead or with existential crysis but they do offer things that HTML5 tech can't dream of offering anytime soon. AAA Gui support is one thing. You just can't (or with very difficulty) do complex rich gui web apps yet. Yes solutions like JQuery UI and stuff try to accomplish that goal. But imo they fail. Yes HTML5 is new, it' a baby. It isn't fair. But people seem to forget that.
Must HTML5 tech support it all and rule alone ? It doesn't have to be. But for most people there can be only one champion the rest just sucks and have to die even if a month ago they thought the opposite.
The other big problem is JS. Poor JS, the weight on it's shoulders is just too big. It's not prepared for the things people want to do with it these days. You must fight with the language to get a minimum of quality of code, modularization, ide support etc.
Have you stopped to think why there's tons of JS libraries to handle problem A, B, C, D, E. etc ? Libraries it good and nice. But they should be extensions. You mustn't have to rely on them to perform every single task with a language and to be able to program decently with it.
It'll be a very very hard task to fix JS. Maybe impossible. The new version won't do it. It'll make it better sure but won't do it. Some people say: "Don't fight with the language, accept it". Must i accept such regression ? I don't think so.
The biggest app i ever made, on desktop, had some tens of thousands of lines of code (C#). It required lot's of modularization. I can't even imagine coding something like it on JS. It's very very difficult for one person. For a team it's nigh impossible. What must be decided is: What is JS for ? Web Pages ? Great. Perfectly doable. Big, feature rich apps ? Forget it. They must be big there's now way. We want nice looking interfaces, responsive, the best user experience etc.
Games, even simple ones ? No way. It get's unmanageable very fast. It's not anyones fault. It's the language's fault. Of course you can write bad code anywhere, but with JS is just too easy.
These are troubled times indeed.