I think it comes down to the individuals. The ones that are retired that I know all tend to spend less. But some seemed to be overly worried about saving money fearful that they may be eating into their savings or capital - even when they have enough to last.
If they are spending less it's through necessity not through choice. All of us want to retire with the freedom to be able to do what we want, when we want. I'm sure those who spend less when they are retired only do so because that's what their finances permit.