If my alcohol ravaged brain does not defeat me...was there not two mid-airs in one day...seems it was about twenty years ago. I do know PHI lost two Jetrangers to tranny mount failures in one day many many years ago.
The traffic problem could be improved if the GOM adopted a method similar to the North Sea....a single common frequency for distinct areas thus all aircraft operating in that sector are on the same frequency. There would have to be more of them....due to the sheer number of aircraft and it would require two radio's in each aircraft....
The answer to the question...how much does an accident cost vice the cost of TCAS....is simple. One can purchase insurance for the accident....it takes capital investment to purchase TCAS....which is much more costly....and thus harms the bonus pool for the managers. (....or could the cost be passed along to the customer some way?)