That is just rubbish, the depth now is much better than 10 or 20 years ago.
You're the one speaking rubbish. I know there are more good players than ever before, but for the top 3-4 players that isn't much of a problem. Since there is so little variety in surfaces and playing styles, it has never been easier to win on all surfaces than it is now. They can just play their own game whether it's on grass or clay and be equally successful. That wasn't the case in earlier eras. Muster, Bruguera, Chang etc were useless on grass. Sampras, McEnroe, Edberg, Becker were never a threat at the French. Wouldn't Nadal have easy days dominating if all tournaments were played on clay? That's basically what's happening. Make all surfaces the same and you'll have the same guys winning all tournaments (as we have today).