Ah, but in those days it was rare to have seats allocated until you checked in at the airport. And you certainly didn't have to pay for preferred seating. The system was far more easily corruptible in favour of staff travel
I certainly benefited a number of times too in past times. But now days you are charged for this, that and the other, so it's quite understandable if pax get grumpy if the airline fails to deliver what they charged extra for.