Not necessarily. More than likely, Laver and Rosewall would have came out with an approximately equal number of grand slams between them.
And just because Rosewall had a good overall head-to-head record against Laver doesn't mean anything when it comes time for the Grand Slams, in which Laver excels. Boris Becker had a 25-10 lifetime record against Stefan Edberg, but Edberg won a big majority of his matches against Becker in the Grand Slams.
Wrong again. The biggest events for pros in 63-67, when Laver was pro and not playing the so-called grand slams where pro slams. Players ineligable for amateur slams, considered these events their most important and they took them extremely seriously, in fact at the time the pro field was far stronger than the amateur field, so there was alot of pride and recognition involved in these events. Laver won 8 of 15 from 63-67, but 0 of 3 in 63 and only 1 final in 3. It is very obvious Laver would not have won any slams until 1964, and even he himself admits that. Based on the 8 of 15 stat, a good estimate would either be 11 of 20 or 10 of 20 had he played regular slams from 63-67; but that is assuming none of the amateurs would have been able to win any slams from the pros. Laver won 5 slams from 68 and 69, so add those to that. At best 15 slams would be a generous estimate for Laver.
The whole point of your statement was to diminish Federer anyway but since you obviously dont have the knowledge of tennis in the 60s to have made an even semi-valid point you end up embarassing yourself. Be more careful next time.