I 100% disagree with this. I do feel there is a place for this, but it is not in the Monster Manuals. I do expect them to largely be large statblocks for monsters (the Compendium info has to come from somewhere).
There is a place for this, but it is in the series we have that includes the Draconomicon and Open Grave.
To me, what you list is largely going to go unused. I might use one monster lair in a book, one or two might give me inspiration. The rest are wasted pages. Give me a Book of Lairs, on the other hand, and I might use more (and am more likely to buy it if that's what I need).