SS I'm guilty of taking the bits of what you said that I disagree with, without acknowledging the positive aspects of what you say. Sorry.
I do strongly agree that sitauional awareness is key. That's about both minimizing traffic density around you and biasing your search for traffic in the high probability areas. That, after all, is what TCAS and similar devices facilitate.
I think you missed my point? I'm not saying see and avoid is going to save you every time, I'm simply saying that fancy gizmos won't either! Take your example ... do you think that a buzzer telling you a bullet is incoming at 2000 mph is going to help you dodge it?
It's not about a "buzzer". If the "gizmo" showed you the path of the bullet some 10 seconds before it arrived, would that not allow you to step out of the way?
The median distance at which traffic is detected in good VMC is about a mile. That's not the worst case, that's the average. At closing speeds of 5 miles a minute, that gives you 12 seconds to assess the threat, decide which way to turn, and physically change the trajectory of your aircraft. The research I've seen suggests that it takes about 10 seconds to do that. You might make it, you might not. But if you get warning of the conflict at 5 miles, or even 3 miles, and it allows you to start the decision making or even evasion process that much earlier, it makes a huge difference to the probability of a successful outcome.