For someone with 20 years experience who has written a bunch of books, I think that's a lot. I'd expect someone in this position to not really apply/interview in the normal sense anymore and to be able to hop around via their network.

The 1000s of applications folks are doing on the SWE subreddits are mostly juniors (or over titled seniors) with not much experience.

Maybe this guy is in that latter category, but it seems unlikely. I think this is just an issue of remote jobs being scarce.