No one remembers loose ends. Most people think that run starts with Anatomy Lesson. It only brilliantly ties it up if you've read the previous run, which most people hasn't.
Nah, I think that it seemed that way in hindsight only because for years the TPBs collected Moore's run starting with #21 and so people feverishly hunted down the relatively hard to find #20. Many reviewers late to hop on the bandwagon who had only the TPB to go from wrote it that way, for sure, but it's a small revisionism. Moore invented the voice he uses for Swamp Thing and writes some of his best poetic narrative as Swamp Thing is hunted to his "death" in Loose Ends. The "roots" for everything that happen later with Arcane start there.
Shit, I sold on for over $35 not long ago, people still hunt down Loose Ends if they got a collection that starts with #20 and Moore fans and Swamp Thing fans realize its worth--it's not forgotten or unremembered by any stretch of the imagination.
If they'd collected Moore's run the other way, the sensible way, that impression wouldn't have developed over the years.