And it's funny, but the IDE is actually more performant in the browser. Well, I was using Aptana before, which is essentially Eclipse and that's known to be slow.
Also, it just feels natural to have your IDE right next to the end product. IDE in one tab, web app in the other.
And yes, we have integrated version control. Based on mercurial. :)
The question is really how often does this happen and how long is it out for. Personally I don't remember the last time my internet was out for more then an hour, and that wasn't even in the last year.
Google Docs must have the same problem, how do they mitigate it?
Vastly better than before though - their offline support is very new.
I can see the always-on scenario playing out ok for some (web-developers, enterprise folks etc), but I don't see how the hardcore C crowd and their hyper-customized build farms would gain anything from it.
Re: Google Docs - you can enable offline editing with Google Docs.