Given that planes still have to have places for ashtrays, and that I predict battery-powered airbusses won't be a thing, I am okay with failing airlines. The Ushuaia/Cape Town railway can't come soon enough.

Is this a problem in the budget airlines space, with Ryanair, Spirit, and Frontier, where the staff actually enforce luggage requirements?

Airlines and passengers optimising for different goals. Not surprising this winds up in a tussle.