That's not really playing devil's advocate.
Golf is also not piano lessons. It takes time to change things. I've been working on a similar thing in my swing for five years now. I check in with @david_wedzik from time to time, every four to six months, but that's about it.
I played piano and the trumpet as a kid. Learning a new piece of music is not the same thing as ridding yourself of a swing fault you've had for 15 years.
I did take piano lessons and was forced to practice 1 hour per day. I hated it because I was forced to practice and didn't put in any effort to really learn. I repeated the same classical music pieces many weeks until it was recognizable as music. When I was older, I took weekly lessons from a different instructor and loved it.
Each individual is different and the time they allow for practice and their dedication will determine the frequency of lessons.
Well, I forget the exact number since it was a long time ago that I read the article. But I do remember the jist of it!
EDIT: And now that I think about it more, I believe it a was a fraction of a stroke difference!
During the summer and early fall, it's 4 weeks. But it depends on what is or is not working.
It's golf. It's hard. Typically, your are also working on integrating the new pattern into your previous worked-on patterns. It's not as if you can work on golf on a daily basis. If someone can get to the range 3X per week, they are doing well. Some also work 10 minutes inside when they are not at the range. And then some of us actually like to play the course - the course exposes your weaknesses.
I find that almost impossible to believe, unless one (or both) of two things were true:
the players routinely gave themselves putts they shouldn't have…
the definition of "appreciable" is much wider than my own.
FWIW, I'd call two or three strokes "appreciable."