This isn't the case for the desktop apps I care about at all. Ableton Live, Photoshop, XCode, MetaSynth, dozens of plugins for same, any number of video editors

This isn't the case for the desktop apps I care about at all. Ableton Live, Photoshop, XCode, MetaSynth, dozens of plugins for same, any number of video editors, look and feel nothing at all like a web app. Web-based versions of these will not be competitive any time in the forseeable future. Your concerns about Apple's policies are legitimate but orthogonal.