All this talk of GOAT debates, one thing to keep in mind that every generation/era had different measures of excellence and dominance.
Even up to the Borg/Connors era nobody talked about the pursuit of the Most Majors, if that was the case, everybody would have played all 4 Majors, and the reality is other tournaments were considered far more prestigious than the AO. Borg and Connors rarely played the AO. Add that there were competing pro circuits back in the early days of Open tennis, even up to the days of Johnny Mac and Lendl you had ITF (?) and the WCT tours, so that there wasn't one standardized tour for the top pros. Rosewall and Laver, while admittedly older, had to skip even Wimbledon a couple of years due to their Pro tour commitments and then there was 1973 when most of the top players boycotted Wimbledon. When I was young, the WCT YE champ title was a huge deal, eclipsing the AO as far as I can remember. WCT title doesn't even exist anymore. Add 4 or 5 years of World Team Tennis in the mid to late 70's which prompted many players from entering the French Open (even undefeated in clay Chrissie Evert!)
To muddy the waters even more, Roy Emerson held the record with 12 career Majors. His Majors were won when the Pros were barred from playing them, and 10 of them were after Rod Laver, as an amateur, had achieved the Calendar Year Grand Slam in 1962 (defeating Emerson in 3 of those finals) turned pro. Unlike Laver who won the Grand Slam again as a pro in the Open Era in 1969, Emerson never won another Major after the Open era.
So rightly or wrongly the perception was never universally held that Roy Emerson was one of the all time greats. It seemed in his heyday talk was still of Pancho Gonzales, Rod Laver, Ken Rosewall, Lew Hoad, etc and before them, Bill Tilden, Don Budge. Of course we will never know because the Pros were banned from playing during the Salad years of Emerson's Major romp. He was the exception as most players like Laver made their mark by doing well in the Majors and then turned pro to make more money. As an "Amateur" Emerson carved out a pretty lucrative financial career, even turning down initial pro offers because he would have to take a paycut. LOL
Still Emerson, it's pretty impressive that he was 11-0 from 1963-67 of Majors Finals played. I mean, wow.
The person who made the public pursuit of Roy's 12 Majors was Pete Sampras. He more than anyone made it the holy grail of tennis. IT was the Sampra era that every top player regularly played all the Majors and was expected to and it became the ultimate standard. So when Pete finally surpassed Emerson's record many annointed him as the GOAT. Of course the irony was it was far from a consensus that Emerson was a GOAT contender when he held the record.
So now we have the Rafa, Federer, Novak era where the cumulation of Majors is the ultimate barometer of tennis greatness. Federer made no bones he wanted to catch Sampras. This has been the only era that all 3 top contenders have won Majors across all 4 tournaments, not to diminish it, but they've all had at least 60 opportunities to do that. Compare their Major appearances to all the players that came before them and it's jaw dropping the difference in Majors entered. Even Jimmy Connors who before them had the longest top level pro career with a 22 years played a total of 57. JImmy Connors was ranked #1 for 5 straight years from 1974-1978 and yet he missed 5 FO's and 3 AO's. Can you imagine a top player today skipping 8 Majors for non injury related reasons?
Of course you start throwing other criteria (understandably) into the mix and the adherents of the Big 3 will choose the criteria for the most part that favors their player.
So my point is while now Majors won seems paramount , it's a fairly new development in the long history of tennis.
