Measuring productivity in software development, or even white collar jobs in general, let alone the specific productivity gains of even things like the introduction of digital technology and the internet at all, let alone stuff like static vs dynamic types, or the productivity difference of various user interface modalities, is notoriously extremely difficult. Why would we expect to be able to do it here?
https://en.wikipedia.org/wiki/Productivity_paradox
https://danluu.com/keyboard-v-mouse/
https://danluu.com/empirical-pl/
https://facetation.blogspot.com/2015/03/white-collar-product...
https://newsletter.getdx.com/p/difficult-to-measure