On the other hand, coax cable was significantly more expensive per length. Compared to RJ, BNC coax connectors were expensive and hard to correctly crimp onto the cable. When computer industry tried to make them cheaper it also resulted in very crappy products.
Unreliable connections were cause of most of the gripe with older coax-based networks. Which is kind of counter intuitive. A properly made BNC is very reliable and still used extensively in electronics test equipment and RF applications. But apparently reliability just didn't scale down cost-wise.
When asking this question, I was more interested in learning about the signaling issues in the different cable types.