From what Arcal 76 has mentioned in his post, NVG was ruled out due to cost. What management always fails to understand that 'affordable safety' is a nice phrase, but one accident that could (possibly) been have avoided due to (in this case) NVG would have paid for the NVG installation and training for the next 50 years. And lives would have been saved.
My condolences to the families and to ORNG.