Almost certainly the most common use case for multiple screens on Macs at this point is notebooks connected to an external monitor, some of the time. On modern Macbooks it's mostly all just Thunderbolt ports too, which are supposed to be interchangeable, people can plug in whatever wherever without thinking about. People may also run a monitor via a TB dock, which again may plug in wherever. Though even with desktops in general, tying meatspace spatial information to port plugin fundamentally seems like a bad idea. Physical screens are much less likely to be moved then a cable, and the number of people who'd prefer to be able to treat the same type of port as functionally identical vs those who want that mental overhead seems low.
That's a poor excuse for shuffling screens that, like rather many (so not a rare bug), don't have unique serial numbers in their EDIDs, just because the user folded the laptop to sleep, and unfolded it the next day after breakfast to continue working/using.
Resolving assignments of cloned screens in the absence of physical-plugging-involving hotplug (that thus only comes from the monitor(s) also turning off when the laptop goes to sleep) by random instead of remembering physical ports/paths to them, across sometime as tame as a suspend-to-RAM, is frankly terrible UX.
Trying to use uniqueness features to be sticky across port swaps is good.... but I'd not be surprised if my grandparents would actually assume the way to swap them is by swapping the ports they are plugged into. Especially I'd expect them to be confused/surprised by swapping the plugs _not_ resulting in swapped content.
Docks with numbered ports make me want to have all things aligned. First monitor left to right needs to connect to port 1 and have number 1 in the system. I know this is not required but feels untidy if not done.
