In many respects bicycling isn't a social activity. The actual riding is often done in near silence because it's hard for two riders to stay within conversation distance for any distance. Organized rides on closed courses are better in this regard, but as the OP points out things like terrain can make it hard for unmatched riders to hold a conversation.

However, one of the best parts of organized riding is what happens when folks aren't actually riding. The AM start area, rest stops, and end of ride venues are great opportunities to meet and socialize. This is one reason I like multi-day organized rides where folks can get together and share drinks and meals at the end of the day. Most one day events are barely worth the time and effort to get to and from them, and rarely offer better riding than I can find on my own.