I have to quicky switch to my earpiece from my wireless earphones whenever I receive a call just to avoid the low quality headset mode. It's so so bad. Not all wireless headsets are the same, however.
Unless Apple or Samsung is using a proprietary protocol between their headsets and handsets, they pretty much are. You'll even notice the degradation of quality if you use your Mic on a Mac or PC.
I've never seen a Bluetooth device that simultaneously supports two active profiles so you could stream audio over A2DP and capture mic over the headset profile. Even if such a beast existed, I doubt devices would know how to handle it.