Since 2009 Fed won 4 slams, 7 masters and 2 YEC, I don't know where you got that "6" number. I count 13.
Left off his Masters. Oops. Typing on phone.
Doesn't change anything.
Yes, Murray dominated with the other 3 players, nobody can't deny that, but we should concur Murray was way below these 3 players.
Bolded is the point. The big 4 is called the big 4 because collectively they completely pwn the Tour. It's not about who has won how many slams, and never has been. The Tour is more than 4 tournaments a year.
Saying "big 4" doesn't imply all those players are as distinguished as each other. Fed and Nadal's records are much better than Djokovic's and Djokivic's is much better than Murray's. The point is that all four are lightyears ahead of everyone else.
It's about who is competitive and who has a serious chance to win big tournaments. Muzz is always there in the mix, even if he doesn't have the Slam silverware yet.