Whichever type of go your prefer, it seems you can't shrug it off as making no real difference.
Chess has faced the same pressures. They have responded by defining ranking lists for three types of chess: Classical, Rapid and Blitz. These are based on time allowances.
If you look at the ranking in Classical chess, which appears to have the highest status among both players and chess fans, and compare the ranking in Blitz, there are some startling differences.
The table below shows the players in the Classical top ten and their Classical/Blitz rankings with the Elo points difference between them.
- Carlsen.... 1/1 (86)
Grischuk... 2/3 (42)
Caruana.... 3/69 (130)
Giri....... 4/13 (27)
Topalov.... 5/>100 (? but big)
Nakamura... 6/2 (91)
So......... 7/34 (62)
Kramnik.... 8/16 (20)
Anand...... 9/14 (15)
Vachier-L. 10/5 (51)
To add some context, a 100 points difference between opponents equates to the higher rated player having a 64% chance of winning. That seems to equate to the old go handicap of B-B-W, so 100 points elo = 1 dan at pro level. (200 points difference makes the winning probability 76%.)
On that basis, Caruana (who is third in all-time elo ratings list) shows much more than one dan difference, and Topalov (a recent world champion) must be at least two dans different. There are other big dan-level differences in the top ten, but of course all of this is magnified if you scan below the top ten.
The list also shows that while some are significantly better at classical chess, for others the forte is in blitz, so it is not the case that everyone's play deteriorates at the same rate when playing blitz.
My first impression is that this puts a big question mark over the elo ratings in go, and that they may need to be recast in the same way as in chess. I'm inclined to wonder, too, whether this lends support to the notion that older and/or Japanese players who are obliged to play too many fast games are misrepresented by the current ratings. I know we have some good statisticians in this forum (esp. Dr Straw), so I look forward to their views.