I think networking is great for your career. It’s easy, and it can be rewarding.
However like any relationship, it needs care and feeding. It’s a bit of work.
If you meet someone new, and you make a good connection, keep in touch. Drop a note after you return from an event, or periodically just send a “how are you note.” If you see the person at another event, at least say hi if you can’t have more of a conversation.
The reinforcement can really grow and strengthen the relationship.