You need to put things into perspective.
In Pete's day, going from tournament to tournament, from slam to slam, was like going from day to night, or night to day. In Fed's era, it is like going from night to night or day to day.
In the current era, with the slow down of most courts, which has resulted in basically one style of play, the cream rises to the top. The cream is Fed, Nad, Djok and Murray. If those 4 players are fit and firing, they'll make the semis of any tournament 9 times out of 10. In Sampras day, each tournament was different, each had its players to look out for and each had its floaters. Honestly when was the last time we heard the term "floater" used when discussing a draw? In Pete's day, and in eras before him, it was used often. In Pete's day, there was no one style of play. At the FO, you had to contend with dirt rats who did bugger all all year except during the clay season. These guys simply did not give a damn about Wimbledon. Then you would head over to England, the dirt rats having disappeared for another 10 months, and then you had the guys with the bullet serves who would rush the net. Do you think Becker had any idea who Doohan was prior to June 1987?
So today, in the current tennis environment, if you are good enough, you will rise to the top, because basically you are playing players who play just like you, but are simply not as good as you. This breeds repetition, which in itself breeds consistentcy. In Pete's day, hopping from slow courts to fast to very fast to medium back to slow, to slower, then to fast, didn't augur well for consistentcy. This has alot to do with why Federer is consistent and why Sampras was not as consistent.
But has already been said, Sampras had the game to blow any one off any any court, and on a consistent basis too. He would have been a top player today, or in Laver's era, or in Borg's era or in the 80s. So before you go quoting any more stats, forget the stats, Sampras didn't always care too much about winning. He was happy to get the monkey off his back remember? He even said in his own book that he didn't go out onto court against Edberg in that USO final to give it is all. So again, forget the stats. Look at Sampras' game, when he was on, he was the most devastating and aggressive player I've ever seen and that includes the guy depicted in your username.