Nobody said we were using 6 months as a benchmark. For a fully fleshed PC MMO like WoW six months is nothing, in console terms it's an eternity. Too many good games coming out to take people's attention, helped by the fact you don't need to upgrade your hardware continuously to play those newer fancier games on console. How many people play a console game for a couple of months, beat it, and move on to something else. Not many keep people playing for as long as Destiny has, except maybe GTA:Online that has been going strong for a year and a half.