Let's stop this rubbish about TCAS. If one aircraft is fitted, and the other has a functioning altitude reporting transponder, then they 'should not' hit.
If both have TCAS, the RAs will be co-ordinated, and they 'should not' hit.
If all pilots have always reacted correctly to TCAS RAs, then my name is Graham Norton. Too little training, and of the wrong type, has led to enormously widespread mis-understanding of TCAS by those involved in its use.
Now if the TCAS action was downlinked to ATC and linked into STCA, in order to allow controllers to back-up the TCAS RA guidance, THAT would be a step forward.
Mind you that's like saying that TCAS shouldn't be necessary. It wasn't, until recently. Now, it's preventing collisions every day. Just not on July 1st.
All this analysis aside, let's not forget the families who are left behind. They don't know enough about this business to achieve a change. We do, and if we can bear their loss in mind, we can take steps in the right direction.