You are probably correct that pros don't put conscious thought into pivoting.Exactly right. Lot of talk on here about what pros do. I'll tell you what they do. It's very simple.
They do whatever is necessary in any given situation to give themselves the biggest margin of error possible. Doing that allows them to be successful to the highest percentage possible.
Bridge or stroke length, stroke speed, amounts and types of english, position routes and many other things are just tools they use very skillfully to give themselves the best possible chance of success.
Of course most will have a default bridge length on a normal shot and though it varies player to player the majority bridge in the 10-12" range.
Watch 20 high level pros shoot in an hour long video and you'll see that with most, unless they have to stretch or need a lot of power they're bridge is nowhere near the natural pivot point of their shaft.
Don't have to believe me, just watch some vids.
Better still, for those who go to big tournaments, ask a few pros how much attention they pay to pivot points. The answer will be...not much.
It has been my observation that when using english, they are very consistent in having the same location on the shaft crossing the shot line, regardless of what the front and back hands are doing. My guess is that that location on the shaft is the pivot point.
Watch some videos with overhead views. The intersection of the shaft and shot lines is remarkably consistent regardless of where the bridge is, and for LD shaft users (pretty much everyone now) is usually at about 14-16".