What load of codswallop. Now we'll have every dogsbody pilot peering at their ADS-B In screens and asking ATC "is that return going to miss us?". TCAS does not require ADS-B, only a transponder (Mode S best). ADS-B In in busy CTAs/zones will be a distracting nightmare for crews.
Having had ADS-B traffic displayed in my cockpit for over the last decade, I beg to report it has vastly reduced the urgency of necessary avoidance of conflicting CAT since I can now deal with them several miles away.
For one example before ADS-B display, ATC once dumped me in front of CAT that required a 90±° bank to avoid. There were other interesting encounters with CAT in Class E - no longer.
As we saw here, ATC can fall short and altitudes can be missed. An ADS-B display is a valuable backstop - for a small fraction of the cost of TCAS.