https://www.yahoo.com/finance/news/s...194843416.html
Gist of article is that because of recent publicity about airline misbehavior against passengers, they don't have the juice to lobby against this bill to kill it. Further, the basis for the proposed regulation of minimum seat width and pitch is due to concerns that evacuation tests have not been run with these high density configurations.
While I am not sure that the latter argument is correct, because certification requires evacuation of maximum permitted Pax capacity, one thing that I do wonder about is whether evacuation tests assume that no Pax tries to bring along their carry-ons. Since it always occurs that a significant fraction do try to pull their carry-ons from the overhead and take them with them, it would seem reasonable for evacuation tests to require a significant fraction of Pax to take their carry-ons.