A question commonly asked when picking microphones is "Which microphone has the best reach?" The problem is that a microphone doesn't reach for anything.
A microphone responds to sound waves that travel to its location. The microphone measures variations in air pressure and provides an electrical output that mirrors those variations. The air pressure variations can be sensed as long as they are within the hearing frequency of 20 – 20,000 Hertz.
I think part of the myth of reach comes from microphone sensitivity. Sensitivity tells how much electrical output, in millivolts, a microphone produces for a certain sound pressure input (in dB SPL). If two microphones are subjected to the same sound pressure level and one puts out a stronger signal (higher voltage), that microphone is said to have higher sensitivity. Therefore, if two people are using two different microphones and singing at the same level and holding the microphone at the same distance, BUT one singer is louder in the speakers, it's not because the microphone has reached out further than the other. It's because that microphone produces a higher electrical output.
Bonus: It's good to note the amount of background noise in a situation can effect the ability to clearly pick up a sound. The reason is the background noise level can be significantly high enough that it either overpowers your source or is high enough to muddy the sound or remove the clarity of the sound.