Audio feedback missing while using headset.

I recently bought an LG G4 phone for work. I have many teleconferences so I use in-ear headset, partly because of ambient noise and because of the severe audio leakage to the environment from the speaker (sensitive subjects)...

What bothers me is that there is no audio feedback what-so-ever from the microphone to the ear-plugs. It's disconcerting, uncomfortable, and it makes me inadvertently shout because I can barely hear myself unless I do.

I sent LG a support request, and they answered "whut?"

Audio feedback from the microphone to the speaker is not some esoteric technical solution, but has been a part of telephone ergonomic standards for a hundred years. Until now.
What happened to employing engineers who knew what they were doing?
What happened to employing programmers and system designers with at least minimal experience outside their own software laboratory environment, aka "the real world"?
Back in the "good old days" when I owned Ericsson phones, this was not a problem.

How do I get back audio feedback in the headset?