> You can't compare Elo ratings over long stretches of time, period.

I agree that you cannot do it reliably, in principle.

However, Bobby Fischer peaked at 2785, and Gary Kasparov peaked at 2851. These are not far from what informed observers suggest--maybe 50 or 100 points off. They are well into super-grandmaster territory. Kasparov would be 1st today, Fischer would be 4th.

But on goratings.org, the top player of the 90s would be roughly 30th today.

My point is that the go ratings are much more unstable than the chess ratings. With chess ratings, you'll be wrong in the details. With go ratings, you'll be catastrophically wrong.