Forgot to add
I said 2 sources are to blame, but you could make it 3 (public, elite, airline). I've said much about the elites and airlines, but the general public, as long as people demand low fares, but expect wide seat, big legroom, etc., it will also contribute to tense situations. As we all know, it all comes from the expectations, for both elites and casual flier, for getting something, but the harsh realities (tight seat pitch/width, overhead bin, set up by the airlines
) will make the uncomfortable situations possible.
I don't know. We should temper our expectations (for both elites and non-elites) but the airlines must do their part to make it better. It is like chasing one's tail...