Why are military & civilian headset plugs different?

Howdy,

Just started taking flying lessons (6 hours ground and 7 hours in the
air) and I've been reading up on everything like accessories,
techniques, etc plus lurking here for a week.

During this time, I noticed the difference between military andcivilian
headsets, and if I understand correctly, the military headsets are a
single plug versus the two plug civilian ones.

I've searched the newsgroup for an explanation why the civilian sector
hasn't switched to single plug system too? It seems like it would make
things easier, less points for failure, etc.

I understand that there's a lot of built in support for the existing
two plug system, but I'd expect the civilian radios to start having
support for both while everyone switched over over a 20 year or so
period.

Is that the case? Do new radios have both types of plugs? Or is there
another reason why civilian headsets use the two plug system?

Thanks!