You remember correctly, but perhaps the facts have changed
Anyway I feel that 20 years, a full generation, is a long time. 2 years would seem more connected with the back story.
As of the current history, it's twenty years since the blood mist lifted. This is mainly because some social function should have started to pick up. Please elaborate on what issues you see with this? How would two years be more in line with the back story?
I'm leaning towards that the mist did not kill 100% but very unpredicably which spread even more fear than predictability. Also I would assume that a lot of people wouldn't trust that it's actually gone. Perhaps the old generation of humans and others had to die away before much travel started. It's pretty flexible and easy to adjust which I think is a good thing.