[TangoLimaSierra]

The extra legroom is in the Window Emergency Exit Rows. Done to provide extra room for egress in Emergencies.

Exactly. I try to get that seat on the rare occasion I fly. On some planes the very back seats have more legroom as do the very front. (Not first class)

[offduty]

You can blame the airlines for this predicament. They were the ones that approached the plane manufacturers to try and squeeze the seats in order to cram more passengers on a flight. I’m over 6’5” and if I can’t get a seat in the emergency exit row, I don’t go.