I don't believe it's a requirement, but if it is;
I think friendships aren't required, on the other hand, acquaintances are, for surviving.
Friends are people whom you trust, tell them what annoyed you, what made you sad, etc... So, if you don't need someone to share these things with (besides your partner if you have one), then you don't need to have friends.
acquaintances are people whom you call them from time to time, ask them for a favor when you need, and return the favor later (or the opposite). are they REQUIRED? not really, but they sure as hell make your life easier. For example:
- you want to start a career and you know some business managers, people who work in the field, and marketers, the least they can do is give you an advice, or even give you a push in what you need (money, recognition, or an opportunity)
a more basic one that happens often, is when you know the waiter or the cashier in a certain place, taking your order first is a given.
That was only my point of view, I'm sure some may disagree with me. Thanks for reading :)