Personally, I don't think that makes sense at all.
An active connection for multiple devices would pose various problems for the designers and the device, most notably electrical pollution of the DAC from multiple devices. No one wants that and intercepting it is very time-consuming and expensive.
A simple switch would make even less sense, since there are external solutions with a protective function starting at $20, eg 4->1.
If an internal switch has a defect, the DAC might also fail. With such cheap external solutions, it doesn't make sense either.
I would also estimate that less than 1 in 100 buyers would use this feature, maybe as little as 1 in 1000.