As to BS fares doomed? I think a big improvement would be a priority Bag Check line (like they have in legacies). In LAS the line was long and they funnel the line into 4 "open" kiosks, where a mob forms. Then they call your name to put on bag tag - which is hard to hear in the mob scene. This is the worst check in I have seen. Line took about 15-20 min.
How nice a perk for Freq. flyer to have a priority check in line -- and at virtually no cost.
Also a priority Security line for busy airports (PHX, LAS, etc.) would help. Guess there is an extra cost there -- but legacies to it and again a real nice perk for Freq. Flyers.
If they had these 2 -- BS (and A list) would be much more valuable to most.