And btw, grass was still fast in the early 2000 and serve and volley was still a recipe for success.
BBC overlaid two serves by Roger Federer, one in 2003, the other in 2008, both at 126 MPH on a similar line of flight. The 2008 serve goes 9 mph hour slower, after the bounce, than the 2003 serve, or 20% slower. The ball also bounces perhaps a foot higher.
This is a tremendous advantage for the returner: The ball is slower, arrives later and sits up.
Despite Federer had to adapt to this unfavorable grass condition in the later years, he was still capable of dominating the grass season.
There's no doubt that Federer would have dominated more had the grass continue to play like in 2003.