There are a lot of these kind of systems out there already - you could cram your cockpit full of them but in an ATC/CAS environment, having separation standards that are enforced is IMO an easier solution. IFR vs. VFR at night (or poor vis) inside the circuit pattern of a major airport just shouldn’t be planned. There are limits to the safe capacity of various forms of airspace depending on their use and commercial pressure should not modify these.
There is also the issue of deviation from your assigned path through the sky because of a perception of risk actually making the situation worse by going against the plan. TCAS is integrated into ATC/pilot operations and formally trained/qualified at both ends otherwise it wouldn’t work.
Civil aviation isn’t quite ready for the whole autonomous agent thing, driven electronically but it’s probably where we will end up. After all, it’s how it started: no real rules, just pilots seeing and avoiding each other (mostly...).