At Wimbledon? Not the surface in itself. If it's slower, it's due to the weather and/or changes of tennis racquet and string technology. The weather has changed Wimbledon's surface in the past and the strings have changed. For example, 1987 and 1993 saw a much higher bouncing Wimbledon than normal due to the hot weather. At the 1996 French Open, 3 serve and volleyers got to the semi finals due to the hot weather that baked out the clay.
Since September 2001, we've seen the Wimbledon courts change from 70% Rye and 30% Creeping Red Fescue into 100% Rye, which is why 2002 Wimbledon was so odd and everyone knew something strange was going on. Also since then, there's been a fazing out of carpet courts until they disappeared altogether after the end of 2006. And also, Rebound Ace has been replaced with Plexicushion at the Australian Open as of 2008, and I think Plexicushion is lower bouncing and faster than Rebound Ace.
There's a myth that back in the 1990s, players serve and volleyed all the time, but that's false. A minority of players did that at Wimbledon (old grass) and on indoor carpet courts, which no longer exist on tour. On other surfaces, the serve and volleyers also stayed back and rallied regularly.