I agree that anointing a definitive GOAT is probably impossible, or at least requires a subjective leap. My point was simply that if you're going to cite random data points, you've got to be more comprehensive about it.
By the way, Laver only won 11 Grand Slams but he won 8 Pro Slams, so his total Slam count is 19. Ken Rosewall won 15 Pro Slams in addition to his 8 Grand Slams, giving him the highest combined total with 23. But Pancho Gonzales is the most criminally underrated GOAT candidate, in my opinion, on account of the fact that he only won 2 Grand Slams, but 15 Pro Slams. Gonzales was competitive into his mid-40s and is a player that many people say was better than Laver.
Anyhow, I'd say you've got six or seven GOAT candidates, all of whom have a valid argument: Bill Tilden, Pancho Gonzales, Ken Rosewall, Rod Laver, Roger Federer, Rafael Nadal, Pete Sampras and maybe Bjorn Borg (if we emphasize peak level). Of those eight, I think Sampras and Borg get edged into a "1b" category on account of being surpassed by Federer and Nadal, respectively, in terms of career accomplishments. Tilden played in such a different time period, but it is amazing that his career spanned three decades and he not only won Slams over a 16-year Slam (from age 27 to 42), but made it to Slam semifinals (either Grand or Pro) over a mind-boggling 28-year stretch (from age 25 to 52!).
As for Rafa and Roger, this debate will go on for years. On one hand it depends upon how they end their careers, yet even then it depends upon whether you prefer the short but massive dominance of Federer, filled out by his long plateau performance, or the ongoing up and down brilliance and multiple peak phases of Rafa. Unless Rafa out-Slams Roger by at least 2, there will be arguments on either side. If Rafa passes Roger by at least 2, then I think all but his most vociferous fans will cede the title to Rafa.
Anyhow, I'd rather say that each of those eight players was the greatest of their respective time periods and generations. Not GOAT but GOATS!