Sure it‘s impressive, but I think it is by no means as „unreachable“ as it was in the past. And I don‘t think the Big 3 set a „record for the ages/eternity“ with their 20 titles. These are the reasons:
- in the past, the careers of players were over much sooner. Players had time until their late 20‘s to win slams, now players maintain a competitive level well into their 30‘s (= much more time to win slams)
- in the past, people played just 3, some (Borg) often even just 2 slams per year. Skipping Australian Open for example. Now they always play 4 per year
- In the past, there were more differences between the surfaces than today, which made it harder to be competitive at all slams
- in the 60‘s there were no slams for pro players. Otherwise guys like Rosewall would already have gotten well over 20 back then (so the big-3 didn‘t do the „impossible“)
- So if you have a career of 15 competitive years (eg age 20-35), you „just“ have to win a little more than one slam per year to reach 20 (Nadal won 13 with yearly French Open alone)
-The Big-3 all won 20 in the same era. If a player of their quality appears in the future without the competition of the other 2, such a player could reach something around 30 slams.
So I think it won‘t be too long until we will have a new player who will overtake the mark of 20 set by Federer, Nadal and Djokovic. People even thought Sampras 14 would be a record „forever“, than it was just for a few years. Certainly the records of the big-3 will not hold for the next 50 years or something. It will be broken, because 20 is not that hard than it was in the past.
- in the past, the careers of players were over much sooner. Players had time until their late 20‘s to win slams, now players maintain a competitive level well into their 30‘s (= much more time to win slams)
- in the past, people played just 3, some (Borg) often even just 2 slams per year. Skipping Australian Open for example. Now they always play 4 per year
- In the past, there were more differences between the surfaces than today, which made it harder to be competitive at all slams
- in the 60‘s there were no slams for pro players. Otherwise guys like Rosewall would already have gotten well over 20 back then (so the big-3 didn‘t do the „impossible“)
- So if you have a career of 15 competitive years (eg age 20-35), you „just“ have to win a little more than one slam per year to reach 20 (Nadal won 13 with yearly French Open alone)
-The Big-3 all won 20 in the same era. If a player of their quality appears in the future without the competition of the other 2, such a player could reach something around 30 slams.
So I think it won‘t be too long until we will have a new player who will overtake the mark of 20 set by Federer, Nadal and Djokovic. People even thought Sampras 14 would be a record „forever“, than it was just for a few years. Certainly the records of the big-3 will not hold for the next 50 years or something. It will be broken, because 20 is not that hard than it was in the past.