I am not a ratings expert, just a (serious) player, chess programmer and amateur chess journalist. I am not sure ratings inflation even exists. If it does exist and you are talking about rating differences between world class players, then you are talking about small differences in big numbers and you are going to get a good approximation to linearity. But it's only approximate because in my previous example the linearity yielded 125 points v 129 points when the key underlying property of the system requires 125 points v 125 points. But unfortunately I don't know the answer to your question 2), I don't know how robust that property of the system is.
Why do I say ratings inflation may not exist ? It is true that in Fischer's time there was one 2700+ player. Now there are 30 or so. That's the evidence for ratings inflation. But it seems likely that the top players are just better than they used to me. Maybe there really are 30 players today who can play at 1972 Bobby Fischer level.
Why do I say ratings inflation may not exist ? It is true that in Fischer's time there was one 2700+ player. Now there are 30 or so. That's the evidence for ratings inflation. But it seems likely that the top players are just better than they used to me. Maybe there really are 30 players today who can play at 1972 Bobby Fischer level.