You serious with that? I highly doubt that anyone in the game has too less microphones to answer someone in World Chat.
When I stopped playing DP, I was at 1k of them (If i remember correctly)
You will see for urself. ppl only use them only if they need anything. for answering u can just whisper the other person so no need to use megaphones. + since they took out compass u dont get as many megas any more and if ppl are like me u dont buy them.