It doesn't take that long to do laundry in a good machine. The wash cycle on https://www.revolution-laundry.com/e...line-help/faq/ machines is about 30 minutes, and dry cycles are paid in 15 minute increments so I'm betting it takes just over 15 minutes to dry a small load so another 30 minutes. An hour sitting waiting in a terminal versus an hour sitting waiting in a terminal and clean laundry at the same time seems like a great use of time. I think the main users would actually be people on long connections though. Often people end up with long connections because that's just the way the schedule runs, not because they want them.

I actually think it could be cost effective despite the stupid airport economics because these kinds of machines could be placed in low value out of the way places. The kinds of places they put toilets, utility closets, and storage rooms around corners behind retail shops or in basements. I could easily imagine having a bank of machines in the Heathrow tunnels if the fire marshals would allow it and I can't imagine any retail outlet paying rent for that space.

But honestly the thing I miss the most which used to be absolutely standard in airports around the world are barbers and hair dressers. There's the occasional high priced premium hipster place in some airports now but it used to be absolutely standard to get a quick 15minute tidy up before heading on a business trip using time you were already wasting waiting for your flight. Or to lighten the mop before heading to a warmer climate. But now it's absolutely a pain having to take time out of your day and schedule a trip to the barber in the days leading up to a trip, just when you're most pressed for time.

But airports have turned into shopping malls with planes attached instead of venues to efficiently get you to the plane and make the best use of your time. There's no way utilitarian things like barbers can compete on rent with a LVMH bag store which can make more profit on a single sucker buying one bag than the barber can collect the whole day.