In addition to the reasons DC and PB gave, the demise of "social clubs" is a sociological phenomenon:
The social club was the local Mob guy's "court": where he presided over neighborhood affairs and dispensed "justice." He didn't just conduct Mob business at his social club: he established a restful, safe, "exclusive" place where neighborhood geezers (most often not Mob-types) could sit, sip espresso, play cards, gossip, and generally pay fealty to the local Mob guy. If someone in the neighborhood had a beef against someone else, they brought it to the "court," and the Mob guy would rule.
Now, I'm not waxing rhapsodic about the so-called "good old days" of Mob life. The local Mob boss didn't operate the social club as a free public service. It was a great place for him to win loyalty, respect, silence--favors--from the local populace. This was especially important in the days when Italian-Americans (especially Sicilians) were the most prejudiced-against white minority in America. For them, the social club was like a touch of home. And the Mob guy could keep his eye on the young people of the neighborhood, looking for recruits.
Today, Italian-Americans are among the most upwardly mobile groups in America. They no longer have a connection to the old country, and don't need the "protection" of a Mob boss. Ambitious Italian-Americans go to college, not to the Mob social club. The Mob is left to the John and Junior Gotti's. The reason that law enforcement was stimulated to successfully tap Gotti's Ravenite and Bergin Hunt and Fish club was that they were hangouts exclusively for Mob guys, not the general populace. The cops couldn't miss.