When the solution depends on future developments, it is just as easy to assume that that will require replacement hardware.
I fully get what you are saying but one AUX jack would make it possible for these to be used as standards and hardware evolve. Else, to keep these going is entirely dependent on Apple updating the OS to support new standards. Yes, Apple could do such things but that is not typical of them. Instead, you need to buy newer hardware to get the new benefits. For example, with this one, you can't even stereo pair with the OG from only a couple of years ago. Want a stereo setup and have an OG version? Too bad. You need to buy TWO new ones.