Come on, this "homogenisation" argument can only be an excuse for those who failed to win single important tournaments like Sampras and Borg. But what does that mean for total Slam count? Nothing, it all cancels each other out in the end. Because now you have to beat every contender everywhere while back than some were especially difficult and some especially easy (and elsewhere the other way around).
To say today it’s generally easier to win Slams is a joke. Imagine what it means if really everything would play the same and you would only play against “specialists” who built their whole game for exactly those conditions. You have to be the ovreall best to dominate and cannot create niches for yourself.
But while I agree though that courts are more similar to each other than in the 90s, homogenisation is still a bit overrated. Just look at Nadal on clay and off clay, and you will see it it not the same.