Microsoft is floundering since new developers are not picking up the platform lock in of .net, but instead locking themselves into Cocoa or Android. The only reason anyone even cares about html5 apps is because it is the only pervasive platform that targets every device ever.Even Microsoft realizes HTML5 is the future.
In practice, web apps are some of the ugliest hacks ever conceived. They take an xml derived fuzzy document language, a tacked on styling language with C syntax, and a malformed script language with semi-Java syntax that has barely improved in 20 years due to perverse standards by committee and terrible original syntax, and try to make real world applications of them. There is a reason people still see tech demos for html apps that look like native toolkit apps from 2000 (note I'm about to be a hypocrite on this).