You know more about this than I do, but I wonder whether the switch to grafting on American rootstocks in the late 1800's (https://en.wikipedia.org/wiki/Great_French_Wine_Blight) might have had an effect on ripening dates. I don't know about grapes, but I think different rootstocks can have a significant effect on ripening dates for tree fruit. A quick search (which I've only skimmed) says this is true for grapes as well: https://www.frontiersin.org/articles/10.3389/fpls.2016.00069.... Do you happen to know if growers in Beune have switched to more modern faster ripening rootstocks?
Rootstocks definitely alter growing parameters. But there are also dozens of different rootstocks to choose from, each with different characteristics. So I'd imagine it'd be hard to pick out an aggregate trend.
Growers will pick based on a whole number of parameters. Soil pH and moisture being two important ones. Also degree of phyloxxera threat, etc.
Given what's happening with climate, etc. I doubt growers would go for accelerating ripening. Pinot is actually already a fairly early ripening variety for vinifera, usually early October or even late September in my climate (southern Ontario).
