The only thing I can confirm is Ben's "No overseas work." At least, when I was working on Hainan Island after they finished their course there, I stayed at the same hotel and was told Bill had spent 140 nights there and Ben zero.
As to the rest, I think the discussion is valid, in that many, if not most, PGA Tour pros mostly put their name on a course, not really design it in any traditional sense. Even some who have their own firms, i.e., Nicklaus worked at routing and concept design, and studied it enough to understand basics like drainage, even if not doing any detail work, where Palmer was mostly a name plate, but there are many photos of him on site visits, but far fewer of them on second or third site visits to the same project. Not really sure about others like Jerry Pate and Davis Love, although I know who could answer for the latter! And I can confirm that many pros who partner one time with an architect are in the 1-3 site visit mode, maybe a day or two looking at plans ahead of time, with varying degrees of interest.
By most accounts, Ben is the outlier to that rule, and is said to truly contribute. But, my guess would be that even in the US, Bill's on site days outnumber Ben's to some degree as a general rule. I'm not sure the exact amount matters. For that matter, it is certainly possible that one partner could make a single observation even in limited time that would improve a design immeasurably, so you have to give credit to both.
On the other hand, all the Beatles songs were said to be written by Lennon-McCartney, but 50 years later, there are books, blogs, and even a mathematical algorithm dedicated to figuring out who wrote each song, down to parts thereof. Curious minds want to know, I guess.