Carry-on luggage was a way of utilizing some of the overhead cabin space. The future will see a much more efficient utilization of that space in aircraft design. Instead of humans handling carry-on baggage, let machines do it.
In the very near future, you will see a conveyor-loader system where you place your carry-on on the belt, and it automatically gets stowed in the overhead compartments. And you will not have access to it during the flight. This will significantly speed up aircraft loading.
Come to think of it, I have a better idea. What if people were loaded by conveyor belt. The seats would pop out on rollers like a roller coaster. Everyone hops into their seat from all sides, and then the whole thing is rolled into the plane. With these two systems, boarding would take three minutes.
I also would like to be a designer for the carry-on luggage conveyor system. I would build in a special feature. Now, some passengers try to pass off a steamer trunk as carry-on. On my system, if the carry-on is over-sized or overweight, it gets shunted off to a shredder. That would make people obey the rules. If this is the future of automation, I am all for it.