In twenty-two years there has hardly been a book that hasn't advanced the metaplot at least a bit (At the least, characters from Prime Runners have been used somewhat to advance plot points). Granted, those promos aren't great (The CT one doesn't even mention the cities covered), but I cannot fathom how this claim can be made with any seriousness.
Then again, I am in no hurry to be digging up/through the past. There's new stuff, new people, new plots to create; and two decades worth of existing metaplot that can never be fully followed up on for any number of reasons. I love the Tir. I want to do a writeup on the Tir with Critias really badly. So as far as Crater Lake goes, there's a lot of room to play with, especially after the events in Artifacts Unbound.