Ouch.
It's another step away from general purpose computing
Not if the web platform itself is taking enormous strides towards general purpose computing, particularly in the mobile realm of B2G:
https://wiki.mozilla.org/WebAPI
http://en.wikipedia.org/wiki/HTML5#New_APIs
In fact, in my opinion the web stack is becoming The Greatest Programming Toolkit Ever Built:
http://blog.arturadib.com/the-greatest-programming-toolkit-e...
It works for incredibly simple things. But that's it.
Depends on what you mean by "incredibly simple". If you look at the most popular apps besides games, it's hard to imagine why they can't be implemented in HTML5.
As for games, stay tuned. Folks are working hard on it:
https://wiki.mozilla.org/Platform/AreWeFunYet
TL;DR: I disagree. The web stack is becoming the greatest general-purpose toolkit ever built. Already it's a great platform choice for building an entire "app" ecosystem on top of, and it's only getting better.
DISCLAIMER: Although I'm not in the B2G team, I work for Mozilla. However, the above is strictly my personal opinion.