Looking at the Mod Actions page, and almost every relatively recent accounts from 2020 until now are deleted accounts.
What's up with that, and what are the reasons (aside from viewing posts beyond the universal blacklist, but that's my speculation) why these recent users are deleting their pages?

That seems wasteful to me.

It seems unlikely to me. I clicked on page 750 of the list of accounts by join date, which gave me a selection of accounts created last April. Only two of them were deleted. (That said, one of the intact ones was named "7thaccountlol".)