Flypastpastfast. You are correct in that it is a fine line between what the customers want and what they will accept. Airline X carried around 3 million passengers last year. (If my memory is correct) Questionnaires are distributed on all return sectors. They are asked to comment on all aspects of their holiday experience and flight. The vast majority of customers seem to be happy. If a customer complains, staff at Airline X encourages them to put it in writing and send it to the CEO.
Airline X has to my knowledge increased the seat pitch in it’s fleet of longhaul aircraft. I don’t know whether this was as a result of the questionnaires giving a less than acceptable score in relation to comfort.
I repeat. The vast majority of customers seem satisfied. If that is not the case, then it is up to Airline X’s customers to indicate this when given the opportunity to do so during the return flight.
Speaking from a personal point of view, I have had this discussion with passengers on quite a few long haul flights in the days prior to the seat pitch increase. I have not had any since.