I don't think it's unreasonable for a 6'4" tall man to want to store his personal item in his bin.

Most complaints are not for people like you. The biggest perpetrators I see are infrequent travelers (who would not even think about these rules and regulations), or DYKWIA-ers that stuff their overpacked carry on, their massive purse, their coat and their duty-free bag full of crap in the OH bin.

Yea if you've paid for additional services (early boarding, E+, etc.) you have earlier access to bin space and airlines even advertise this as a perk of early boarding services but I don't think it's unreasonable to ask someone like me (a bit shorter than 6'4") to see if they can hold onto their jacket or put it under their seat. Obviously if you're on the taller end of the spectrum, no considerate person will want you to suffer a 6 hour transcon with your knees at your chest..

The harsh reality is that the pricing scheme has encouraged the average traveler (not us) to overpack carry ons and fit everything they absolutely can into whatever they can bring on board to avoid extra fees. A lot of travelers now are students, young people, and families that may not be able to afford early boarding, check-in bag fees, etc. All I really ask for from people is if you can reasonably fit a small item (purse backpack), under your seat without discomfort, you should do it to clear some OH space for the other pax.

While traveling through AUS/NZ, I was impressed with their "check-in everything" system as opposed to the US system where everyone carries stuff on. It sped up boarding, caused less of a hassle on the plane, etc. You'd assume airlines would profit from this as well, but I can see the merit in business pax needing to make a hasty escape as soon as they land