We need better technology than transmission overlaps.
Store-and-forward combined with transmission urgency (1. Mayday 2. Pan 3. Regular reporting. 4. Requests)
Why the hell do we use 1930s radio transmission technology when we have far better available right now.
MIMO directional antennae, transmission packet based, ability to use overflying aircraft as repeaters, full fidelity rather than scratchy crap.
Couple that with always-on-GPS-IN positioning (so you don't hear stuff that's 40NM from you) and have an efficient radio system.
Less operators required, no transmission overlaps, priority messages are sent through-relayed (with position data). Heck you could even have an "I'm completely rooted - more details to come" button on your dash.
Why do we continue with this outdated technology when we could develop far better for so little cost?
Down low at < 180 knots: don't care about overflying airlines at all.
Down low at < 2500 AGL on descent. No interest in anything > 40NM away.
Couple that with full ADSB reporting also on a store-and-forward basis (higher aircraft broadcast info about everything they "see")
Really, why can't we do this?