I just don't think Sonos speakers are built for that type of use case, they are first and foremost a wireless speaker and always have been. They were never designed to allow for devices to plug directly into the speakers, as it wouldn't then be controllable across the array of other Sonos devices, which is the point.
I agree that it wouldn't take much to do so and it would increase its accessibility, but I just don't think they have an appetite to do that.
The Sonos port device which they have had to allow you to physically connect devices has always been atrociously expensive. To think that I could buy two of their rear Sonos speakers and still have money left over be cheaper than the port is just silly.