Just for the sake of argument, imagine you aren't the only one with the knowledge the competition wants. Say there's a 10-person team where each shares the knowledge. The competition only needs one to rapidly close the gap. That would mean the company would have to pay 10x what the competition is willing to pay for that knowledge in order to keep all ten employees faithful. The competition can make a $1 mil offer to each employee, one at a time, that the company would then have to beat. That gets ugly pretty fast.

That said, this does seem to be an edge case, where the general rule causes more harm than good.