It’s shocking how little movement there is year to year when .34 points separate 125 and 150. It would seem that a few submissions could create greater volatility.
This is a good point, although upon reflection, it makes sense. Consider Longmeadow, which is tied for 150 and has an average rating of 6.7. Suppose it has 50 ratings (I don't know the exact number, but a lot of these courses are in that vicinity). Suppose a new rater plays Longmeadow, thinks it's the greatest course on the planet, and gives it a 10. That would bring its average score up to 6.76, and now Longmeadow is 138 instead of 150.
Furthermore, as much as I like Longmeadow, nobody is going to give it a 10. If a rater did give it such a rating, they would probably get a call from someone at Golfweek asking them to explain their thinking, and they probably couldn't justify such a score. So, fortunately, these courses have enough ratings that one crazy rating isn't going to affect their position much, and you would hope there are safeguards against crazy ratings.
Someone might really love Longmeadow and give it an 8, meaning they personally think it should be in the top 25. That's obviously a really high rating for Longmeadow, but I can imagine one reasonable person who feels that way. Even in this somewhat unlikely scenario, Longmeadow's average score goes up to ~6.725, and it's ranking goes from 150 to 145. So it would take more than a few outlier ratings to meaningfully shift the relative positioning of these courses.
On the flip side, consider Wilshire, which is currently tied for 124. Suppose it also has 50 ratings, and suppose a new rater comes along and gives it a 0. Its average rating goes from 6.87 to ~6.734, and its ranking goes from T124 to 144. In principle, it's easier for one crazy rating to pull a course down than it is to pull it up, but even then, one rater can't move the #125 course very far. And no reasonable person would rate Wilshire a 0. Suppose they really didn't like Wilshire for some reason and were in a really bad mood, maybe they would give it a 4, which would bring its score down to 6.81 and its ranking down to 131.
So if there's enough agreement between the raters and enough raters who have played each course, the rankings won't be very volatile, even if the margins separating courses are small.