Evolution. 1.e4 was naturally selected over the course of centuries because it's the 'fittest' move.
It's Common because it's what most people teach beginners. We beginners don't care if e4 or d4 is Better. We just want to play Ruy Lopez and Scotch Gambit. And if possible mate in 4
Mainly because 1.- e4 is more tactical from a beggining than 1.- d4 or c4 for example, so most begginers play 1.- e4 because of the tactics and less positional play.
D4 is an attack game for black and with and e4 is for white attack and black is in diffence.
Thank you
