I agree that many airlines are doing everything they can to get every nickle they can out of fliers. Most posters on this thread know that, too. It isn't right, but it's the way many airlines operate now, & fliers have to deal with the realities of current American air travel.
But the issue being discussed on this thread is people being asked to give up seats they paid extra to choose in advance, for the benefit of those who chose not to pay extra in advance. That is simply not fair to those who paid extra for the privilege of sitting in those seats. You've got to admit that.
I agree airlines should have better policies, but pressuring other passengers to give you their premium seating isn't the way to get the airlines to change. Only customer complaints to the airlines, complaints to legislators to lead to & maintain consumer-friendly legislation, & refusal of passengers to fly on non-family-friendly airlines is going to change the airlines' game.
Until the change happens (if ever) those who refuse to pay to ensure their families sit together, while at the same time claiming that their families cannot sit apart, shouldn't fly at all.