From my view, all it seems reducing the speed limit has done is create a barrier between those traveling a reasonable speed and what the road is designed for (70-75 mph) and those following 55-60 mph. Driving it recently, I noticed a lot of tailgating, brake slamming, weaving in and out, because of the speed differentials.
I don’t think the low speed limit has helped anything, except to make people in power feel better.
I still don’t see a reason why a lower speed is warranted from an engineering and traffic standpoint. It’s a straight road that traffic routinely moves at 70-75 mph when not congested with often little issues.