As much as fpgui spelled the doom of Lazarus.
Nice little dig there. 
Well, it is incorrect in the sense that for fpgui maybe applications can be found. For docs that really duplicate content (like the quoted website), that is a bit harder. Specially since it is in the same format as the ref manual. (short lemma's with short examples that only show the feature in a minimalistic way).
While I always was a bit doubtful of the msegui/fpgui claims to be a realistic substitute, and extremely dislike the way advocacy is done for fpgui and msegui, since Lazarus has a fairly heavy LCL <->widgetset interface, something with a lighter makes a good complement. for special cases.