Oh I think progress has been made, retrograde progress. Economists as less competent now than they were back then.

It is exceptionally difficult to prove economic theories because experiments cannot be repeated. The variables are always changing, and there is far from complete control over them.

Microeconomists and behavioural economists do indeed conduct repeatable experiments. This is more difficult for macroeconomists, of course, but the same is true for many sciences, such as theoretical physics, climate science or much of biology.