Generally, the only way to gain points is to take them from someone else.
So ratings deflate when people study chess and get better.
Then they take points from people who have not gotten worse.
Inflation can happen when lots of high rated people keep playing, get old and their play declines faster than their rating.
Both happen at the same time. My guess, without any data, is that deflation is on average greater than inflation.
Generally, the only way to gain points is to take them from someone else.
So ratings deflate when people study chess and get better.
Then they take points from people who have not gotten worse.
Inflation can happen when lots of high rated people keep playing, get old and their play declines faster than their rating.
Both happen at the same time. My guess, without any data, is that deflation is on average greater than inflation.