Djokovic and Nadal beating him at his own game added with more offense and Fed just offensively bulling him and teeing off winners.
And then Murray's injuries helping 2 of them build bigger leads
I have always believed that Andy Murray made a mistake by playing as a counter-puncher.
He is 6'3" and if you look at any other athlete who is Andy's size they always look to play offensively.
The matches that I've seen Andy play brilliant tennis were the 2008 US Open semi-finals against Nadal and the 2012 Australian Open semi-finals against Djokovic.
He lost the latter in five sets, however, Andy was playing smart and aggressive tennis.
He took the ball early off of the return of serve and he wasn't allowing himself to drift back behind the baseline.
These were the matches where I felt like he was legitimately close to being on level with the Big 3.
The guy under-achieved. He could have easily won another two or three grand slam titles.