"It is tempting to say that a proper discovery plan in the federal district court litigation - which let's recall has only just started - would indeed drill down into those granular facts. The case might actually see that sort of intense and relentless discovery. ..."
There are two possible theories of government liability. One is that the accident was the result of negligence by the low level people, the helicopter crew and possibly some ATC people. The other is that it was a system failure in which higher level people placed a greater priority on keeping traffic moving than on keeping things safe.
The second theory has a serious flaw from a legal point of view. If it is true the government is likely immune from paying damages because of the discretionary function exception. So why would the plaintiff's lawyers waste time and money on trying to establish a theory under which the government is likely immune when there is a perfectly viable alternative theory with no such difficulty.