[#] "Never" is a long time. Certainly "not soon"

We have these automated warehouses and factory floors with robotic carts that can precisely navigate, pickup and deliver loads without a lot of infrastructure needed, that's kinda where I'm coming from.

I'm thinking the solution would have to work with the existing sized doorways for it to be adopted.

Realistically, there's lots of ways to handle the boarding/alighting process better, but we're talking massive extra expense in new planes and airport modifications in order to shave ten or fifteen minutes off the turnaround time. Probably not even that much, since passenger loading and unloading generally isn't the rate-limiting step.

Everybody has opinions on how airline travel can be improved, because airline travel provides people with many hours of downtime with nothing better to do than to think about how their experience could be improved. (This is also the reason there are so many stand-up comedy bits about airline travel.) It's probably much more profitable to think up ways to improve processes which most people don't see regularly, like... I dunno, concrete pouring or tree felling or fiberglass bending or... other things which don't spring immediately into my mind because I can't see them out the window thus demonstrating how obscure they are.

A good first step would be to get back to having the a majority travelers check their luggage. A lot of the delay is by everyone bringing overflowing carry on luggage when the planes don't have room for every one do so.

The machinery to get the seats in/out will be heavy, mechanically complex. This eats into revenue. Might not even work with existing airplanes.

You'd need to have machinery in the boarding lounge - at every airport the plane visits.

You don't really need this everywhere - people can just get on/off in the legacy mode - but when you visit an airport that lacks the gear you're just hauling dead weight around.

Okay, so we design a plane from scratch, and retrofit the terminals in the US ... but then you've got a plane that can only be used in the US. And one that can't be resold to Elbonia Airways when Northwestern is done using it.