It is easy, I have explained already several times.
In totally polarized conditions (with different competitive game styles) you would expect the top players winning a LOWER nº of GS (than in an era of homogeneous conditions and one unique game style), BUT if a player is "the best of the era" for many years, he will be nº1 for many many weeks too.
In another words, polarized conditions and competitive styles VS homogeneous conditions and one unique competitive style, impacts the nº of total GS won by the top players, BUT it does NOT affect the nº of years (or weeks) at nº1 in the same way.
Again, the decathlon exmple:
A man who is the best at decathlon can very well be the nº1 (at decathlon) for many years, but he will never win, say, 8 or 9 out of the 10 decathlon events (in each decathlon competition) all the time (in fact not even once has that happened) because such 10 events in one decathon are vastly different.
On the other hand, if we create a "homogeneous decathlon", consisting of 10 times running the 100 m race in each "homogeneous decathlon competition", then the best at that (currently Ussain Bolt) not only will he be the best (at that thing) during many years (like the previous example), but he will also win 9 or 10 out of the 10 exactly identical 100 m races of each "homogeneous decathlon competition".
I hope this makes you understand why polarized conditions and styles VS homogeneous conditions and style, affects tremendously the nº of GS won by the best player (players) of the era, BUT it does NOT affect the same way the years (or weeks) at nº1 by the best player of the era.
Lendl and Connors dominated given eras (that is why they were nº1 for so long), but in their respective eras it was much more difficult to win different GS, that were played on totally vastly polarized conditions, against players with totally different playing styles each suited to specific conditions.
In the current era, not only Nadal, but also Djokovic will get to 10+ GS soon but neither will get to 200+ weeks at nº1 (probably not even 150+ weeks at nº1).
In short, trying to compare numbers from different eras is, most of the times, senseless.