But that's not relevant to the parent's point, which is "If all open source, such as Linux, was BSD licensed, then only proprietary unixes would be common", which I happen to agree with.
Linux would have been further behind because all the proprietary unixes could take the best parts, without giving back (like Apple did/does with BSD), and all those thousands of full-time employees working on Linux would have created value for the shareholders of their employers, not value for the Linux users (like they currently do now).