Correct. In the case that it stops transacting, the value of bitcoin as a system would be zero. In the case where the costs are larger than the value produced,

Correct. In the case that it stops transacting, the value of bitcoin as a system would be zero. In the case where the costs are larger than the value produced, but are not paid by the bitcoin system (external, you might say), then it would still have net negative value, but continue to operate.