I wholeheartedly agree with your analysis. And I would even extrapolate that the size limitation of DLP means it will be harder for them to make affordable panels beyond 1920x1080. A 4K rez panel will be 4x the size of a 1080p panel, while over time a theoretical 4K LCD panel will eventually shrink to the same size as a current-gen 1080p LCD. 4x the size means 1/4 the yield.
Two years ago when I started planning my room around an eventual move to front projection I pretty much assumed it would be DLP. Over the course of my year-long remodel I have shifted my options to almost entirely LCD.