Would you agree or disagree that no matter what anybody had proposed as a potential way of gauging moral progress, you most likely would have disagreed with it

I disagree with that hypothesis. I further note that I evaluate claims about value metrics "if taken to the extreme" differently to proposals advocating a metric to be used for a given purpose. In the latter case I consider whether it will be useful, in the former case I actually consider the extremes. In a forum where issues like lost purpose and the complexity and fragility of value are taken seriously and the consequences of taking simple value systems to the extremes are often considered this should come as little surprise.