All the McD*nalds in my area have been upgraded with order kiosks. Regardless of all the controversy around self-checkout, and minimum wage, and automation taking our jobs, I personally love them. I can take my sweet time composing my order, I can see the full selection (such as it is), I can see pictures and prices clearly without having to strain my eyes to read 12pt font on the tableau, and I don't have to shout at the cashier to be understood or struggle to hear back. I really believe this is the right way forward.
My only complaint so far has been that the order kiosks only accept card. There is actually a way to pay by cash that the machine never lets you know about - you have to press "cancel" on the keypad when it asks to insert card, and then the screen gives you an order number to give to the human cashier (each store still has one register open) so you can pay in cash. So I still have to wait on line, but at least my order selection is locked in, I can have exact change ready, and there isn't usually a line anyway anymore.
I know all yall Europeans are proud about your nearly total transition to cashless economy or whatever, and you like to boast how not a single euro banknote has graced the inside of your wallet in months. However I personally like cash, and I genuinely believe that a cash payment system is a necessary element of a liberal democracy and secure society. So at least understand my pleasant surprise when I saw these reverse-ATM cashboxes at this restaurant. They work and were being actively used too! (It spat out my dollar coins though, those bastards!) I hope they find their way into more places.
I'll bet this is why McDonald's was fine with the $20 minimum wage increase in California. They'll just use kiosks that smaller places can't afford, to offset the new labor charges. But then smaller places won't be able to appeal to employees, since they will be paying less than half of what the chains pay. The result will be fewer actual jobs available, more pressure on small burger joints to shut down, and few people actually benefitting from the new wages.
They've been the most vocal opponent to $15 minimum wage increase in New York, which I've always found odd, since they'd be the ones to most benefit from it via competitive advantage, as you said, due to economies of scale. They've been making threats the entire time "We'll replace cashier with computers! If you raise the wage, we'll totally do it, you'll see!" and I'm like "Dude, if you had the capability to do it, you gonna do it either way anyway, why you extorting us?"
I guess the smaller competitor restaurants will need to get kiosks as well. They can't develop their own in-house technology like the big chains do, but they can still purchase 3rd-party ready solutions, like all of them have already done with online ordering. Slightly more expensive to use 3rd party, but that's economies of scale for ya.