That's all well until you have external content (e.g. blog with comments or blog roll headlines). Many an enthusiastic Web author in the 2000s migrated off XHTM

That's all well until you have external content (e.g. blog with comments or blog roll headlines). Many an enthusiastic Web author in the 2000s migrated off XHTML again. Not because getting it right is too hard (each fix for each problem is quite straight-forward and often trivial), but because when you have the choice between having a completely broken page/site until you have time to log on and fix it and having a miniscully broken part of a page that's easily ignored by a visitor, then the idealism was just too bothersome. Unfortunately, that's human nature. Also see: rms's principles as exemplified by his life-style and how many follow his example perfectly.