You seem to make a huge logical leap based off someone's facebook page. First off, going through facebook and comparing yourselves to others is one of the most poisonous things you can do to yourself psychologically.
If you really wanted to understand these people and if they are so sociable, you can simply go out and meet them and see how they relate to people. You'll find that most won't meet your idealized version of what they are like from a facebook page.
You seem to make so many assumptions about them and the quality of their relationships simply based off facebook. Simply put there is an inverse relationship between the average quality of a relationship and how many active relationships you have. That girl seems to have a lot of friends but if her mom got sick and she needed someone to watch her dogs for 2 weeks, how many of her facebook friends would actually come through for her? Probably not as many as you clearly seem to think. And that number is probably closer to the close friends most normally sociable people have as well.
And if she does indeed have a ton of friends that can come through for her, it's mostly likely she had to churn through 10 people for every 1 person she was able to convert into a stronger friend. That is an admirable work ethic applied to a social life but it can also be very taxing too. Each relationship is a reciprocal obligation. If she can count on 100 people to help her out in a time of need, almost always those people will expect the same of her. Maintaining that many relationships is more work than you seem to think.
Plenty of people have jobs that require them to have rich social circles in order to get enough referrals or they are in business and constantly need to find new investors or customers. Lots of these people can look like social butterflies but many are also simply doing a job and networking is just something they see as part of their work. Many may actually be high-functioning introverts adapting themselves to their circumstances. The amount of failure for every success is simply astronomical in normal social situations. It's like the number of dates you can get versus the number of girls you ask out.
There is definitely some truth to people who are social butterflies. They are better at relating to others and empathizing with their concerns. They get a lot of personal satisfaction from being more involved in people's lives. They also put a lot of work in socializing, churning through a lot of failures, constantly meeting people, and place new obligations on themselves for each relationship.
At the end of the day socializing is simply a means to an end. Happiness comes for most people from having a few quality relationships: a good marriage, a few good friends, a good relationship with your parents, etc. If going beyond that doesn't seem worthy to you in terms of the process involved or the marginal benefit in happiness, don't sweat it.