Earlier quoted context omitted.
This sounds like it might be faster, and I might like it for solo business trips, but getting on/off with my family is not optional for me. Assuming most multi-passenger groups feel similarly, and assuming solo business passengers represent only ~40% of the population, the impact of such a system (which would require substantially more passenger discipline/planning) would be pretty limited.
> getting on/off with my family is not optional for me If you’re getting off with your family you should just wait for everyone else to exit first anyway unless you have a connecting flight with no time margin or something. Families are super slow to deboard planes. If your kids are young, you should probably be allowed to board first before other travelers. A column by column rule wouldn’t apply to you either way.
Column by column would never work. Most people like leaving together with their friends and loved ones who are sitting next to them, regardless if they are families with children.