I read a blog post blaming deregulation for this sort of thing.
Through deregulation, the prices dropped and the hoi-polloi could fly. And by cramming as many of them into one plane an airline could make loads of money. And if you wanted a share of that sweet, sweaty cash you had to follow suite. This then became such a money-spinner that only that business model could survive.
And now everybody, rich and poor are jammed into uncomfortable planes like sardines jammed into some sort of...thing.
And women pee in the aisles.