@avs I only realised why it is so after some delivery men called me that they're arriving (I rarely get calls; the #Philippines is after all the #SMS capital).
I noticed then that putting the phone on your ears doesn't give much clarity because the speakers are at the top and bottom sides of recent models today, in the desire of manufacturers to clear the front screen. (The front camera is the only one left.)
The workaround is to place the receiver speaker sideways; and when talking, to play the mic side in front of your mouth (or speak really loud)
In some models, what they did for the receiver speaker is they turned the volume up, that it sounds like you're on a speakerphone mode; so you don't have to put it sideways. If you turn on the speakerphone mode, it becomes even way louder.
Problem is, not everyone is switching to earphones. I guess, once Generation Alpha replaces us GenX, GenXennial, that is when talking through earphones with mic will become common, and there will be less sideways / walkie-talkie phones. ^_^;;
Still, I don't know. Usually when we receive calls, it was when we don't have our earphones ready. And I preferred wired because I wouldn't notice if the wireless ones fell from my ear. :P And wired ones are sometimes in the way.