I've had no trouble playing with people in a crew.
Someone just creates a new crew-only MP session and invites everyone.
If people want to do heists, they invite each other.
If they want to do jobs or missions they invite each other.
If people want to simply fuck around in the world, they meet up with each other
Maybe if you're solo in a public game it sucks, but there is absolutely no problem playing with people you know