It's interesting, Krav Maga makes similar accusations about "regulated" sports like the ones you mentioned. Its argument is that on the streets you're not both following the same rules on the fighting ring, you're using guns, knives, pencils, baseball bats and kicks to the groin, almost always facing multiple opponents at the same time. There's nothing in the sports you listed that prepares you against that.

That said, I agree that simulating twisting the weapon out of someone with a gun pointed at your forehead with a fully extended arm might lead to a boost in confidence, but not so much of a boost in survival rates. I'd still argue that your chances are better with techniques fine-tuned for the streets, rather than the ring.