In (good) open source projects, the frameworks developers are also app developers. The difference is obvious when you compare the architecture astronautics of a framework built following "best practices" and one extracted from living code. WebForms looked great in developer conferences, but it made stuff that just comes out of the box in Rails like nice URLs or common layouts a royal pain. I left that world behind 5 years ago, and I hope it has improved, but I have no intention to go back.