Your analysis seems to point to Laver as the GOAT. EVERY other player has at least one gap in his resume. Maybe Gonzalez or Rosewall could have won a career Slam if they had been allowed to compete in the 50's or early 60's. Maybe Tilden would have beaten the French Musketeers on clay if he had had the opportunity. I don't think that we can assume these things, however. I'm reasonably comfortable with the selection of Laver as the GOAT. The difficult part of the assessment would be to rank the next 4-5 players after him.