There's not necessarily a correlation between being an extrovert and interesting, or having hobbies and lots of friends, though. Some people live very quiet or mundane lives without any fancy hobbies, jobs, or views, but are just naturally hilarious, or really good conversationalists who make others feel listened to when they chat, or just nice, kind people who always help friends out, so are very popular.
Other people might have wonderful hobbies but listening to them bore on about them without any input from anyone else makes everyone want to avoid them!
People who don't have any interests at all are generally pretty boring though. It's perfectly understandable that people with young children struggle for time to actively do hobbies but I've never understood why that means they stop having any interests. Of course you might not have as much time to devote to them but why would your interest in history or politics or foreign cultures literature or the environment or football magically stop once you've had kids? It's easier than ever now to listen to podcasts or flick through an online newspaper or do 5 minutes a day on duolingo while cooking tea/breastfeeding/ironing/doing the school run, whatever.
If i asked someone what their hobbies were or what they did in their spare time, I would find it completely understand able if someone said "I love reading, death metal and rugby but i don't get enough time to actually go to gigs or play for my team at the moment so I just listen to music in my car and watch the matches at home." Whereas if someone said "I don't know, nothing really, watch a bit of tv" honestly I probably would think they were a bit boring!