Earlier quoted context omitted.
Even with multi-browser support, it isn't that bad . But we're not talking about websites here, are we? We're talking about using HTML/CSS/JS to build native apps for mobile devices - which are by and large webkit-based. This greatly simplifies everything.
Oh really? Let's take my webkit-based mobile browser then and look at an instagram picture. Hm, it's cut in half and I can't scroll. Mobile web apps are actually iOS webapps that most of the time work on Android. Stop pretending you actually care about standards and cross-platform, you're only interested in doing less work, learning fewer things and holding users firmly by the balls in the cloud.
"Holding users firmly by the balls in the cloud"? If your service already resides in the cloud, the technology you implement your client software in, hardly matters, no? Facebook app, whether is HTML5 or native, is largely unusable without a persistent internet connection. Yes, I am interested in doing less work. I do care about standards, thanks. I certainly wouldn't stand in the way of anyone wanting to learn whatever they want. If you want to build an app to learn Objective-C, all the power to you.