Do you think Laver would still have won slams during those years, 60-62 if the slams were open for the pro field?
As oppose to Gonzales, he was a beast. Big, big Champion.
If Laver was an amateur and had the same strength he had in real life and entered the majors without experience against these top pros (assuming the top pros were also the same strength they were in real life) I believe he would not have won a major in the years 1960 to 1962. However if Laver played Open Tennis all his life (assuming there was never an Old Pro Tour) and played these top players he may have won a number of majors. Remember Laver was initially slaughtered by Hoad and Rosewall when he first entered the Pros in 1963 shortly after winning the amateur Grand Slam. But we also have to remember how quickly Laver improved and adapted his game to the Pros. Laver was number two only to Rosewall by the end of the year and by 1964 he was perhaps the best player in the world. Laver won two Pro Majors that year and defeated Rosewall 15 out of 19 matches.
We all tend to play to the level of our competition. The Pro Tour in those days was unprecedented competition, perhaps the highest level in history in tennis. Legendary Pros like Gonzalez, Kramer, Hoad, Rosewall, Sedgman, Trabert, Segura were constantly playing each other often even in the early rounds. There were no easy matches. Rosewall himself said that once Open Tennis started the average level of competition in his case dropped. At least he said words to that effect.
Imo it's no coincidence that Laver's winning percentage went up when Open Tennis started because he could easily beat some of the easy marks in the early rounds which he didn't have in the Old Pro Tour.
I don't think Gonzalez, Rosewall, Hoad or Segura would have reached the level of play that they attained playing in the Old Pro Tour if Open Tennis was around.
I don't think it's odd that Gonzalez, Laver, Rosewall, Segura played to a late age relatively speaking on the Pro Tour. I think that they reached such high levels that even in a declining period in relative old age that they were still top notch players.
If Nadal, Federer, Djokovic, Murray, Ferrer, Tsonga, Wawrinka, Berdych were constantly playing each other every week they would all improve. That's what happened in the Old Pro Tour.
Edit-Since we are discussing the Old Pro Tour there has always been a lot of disagreement on the subject of Roy Emerson and his greatness. Emerson never played the Old Pro Tour and remained an amateur. Emerson had an awesome record in the amateurs.
A lot of the disagreement involves Gimeno and Emerson. A poster used to vehemently argue that Gimeno was clearly superior to Emerson and frankly I agreed. However I did think that if Emerson turned Pro he may very well have surpassed Gimeno.