A Producer surrounds himself with quality people (most of the time subconsciously). He then invests in their emotional banks, without any prejudice. This is how a Producer can be a resourceful person.
A natural Producer is someone who does all of the above without even trying. This is because his natural mode or instinct is to 'give'. And when the time comes, people would naturally want to help the producer.
A producer who is an opportunist is different. Yes, he/she may also be a resourceful person, which makes him/her an effective producer. But an opportunist just withdraws from the emotional bank. Rarely does he/she invests, or do something for other people. This may work for short term, but less chance in the longer run.