[btilly]

The answer is that any entrepreneur who focuses on what their competition is doing rather than what they are doing is guaranteed to fail.

There are far more likely ways for SpaceX to fail than that some random professor replaces rockets with a drive using novel physics. And even if said professor does produce that drive, it wouldn't threaten SpaceX's main business unless the drive was able to produce sufficient thrust to escape the Earth's gravity well. (Flash notice, not even the professor in question thinks it will.)

Therefore Musk should continue to be focuses on what he is doing and not even think about this unless there is a working prototype validated by NASA.