In chats with my family this topic has come up several times. My current belief about this topic is that unless you value building relationships and work hard at building them with others, you limit your world.
You can either build those relationships or buy them.
If you build them:
Realize that they take time to build and rightfully so. Networking is a mutual exchange. It's not just about what you can gain from others but also what you can offer and contribute. Building relationships should involve a genuine interest in others and a willingness to support and help them as well.
If you buy them:
Referrals help, but you will need to pay the price to see the show. Sometimes there is buyer’s remorse. Sometimes it was worth the cost of admission. Generally speaking, these relationships are transactional at first. This may change in time, but this is how these relationships start.
Additional Thoughts:
In either situation, I always let people reveal themselves to me by their actions and less by their words. Words are easy to speak but actions reveal intent and showcase follow-through. If you think in generations like I do then you value the first option most.