But, he does have a point. Sure, it would be great to have
more sources of inspiration and possible even sources that will directly reference D&D lore the way WOTC could, but, it's hardly necessary. I mean, I had a discussion here recently telling me that a new player could never know what an abbey was because it wasn't detailed in the DMG construction rules.

I'm not saying you're going that far, but, there are those here who are apparently incapable of looking beyond the game books for any source of information.
I mean, if someone doesn't know what an abbey is, and cannot be bothered to take the 30 seconds to look it up on Wikipedia or in a dictionary, then I despair on the quality of any campaign developed by that DM. Which does roll back into the idea of DM's being lazy. Yup, it's nice to have books from WOTC, but, in the absence of those books, it shouldn't be too difficult to look for other sources.