And people don’t need to meet in a common area to socialize anymore. You can watch a movie or play a multi-player video game wherever you (and your friends) happen to be. My best friend lives across the country right now: thanks to bluetooth earbuds and cell phones, last night we were able to talk for hours while carrying on with what we were doing…a conversation that would have been so break-the-bank expensive when I was younger that hanging out with local friends would absolutely have been the only available choice.
Also, fewer people have “free time”. If your boss can (and does) email you with some changes in the evening, you’re not going to the mall to hang out.