Did you notice this post in the Road forum about the cycling distance records?
The record for most miles cycled in one year has been standing since 1939. One person tried to beat that record in the 1970s but his attempt was disqualified.
I find it interesting that the record has stood for so many years. Do people just have so many more things they need or want to do, in more recent times, that we don't have time or energy or desire to ride the kind of distances mentioned in the link in the original post of that thread?
I've done a little over 14,000 km one year, but I was off for 3 months of that year on a bicycle tour (and the Great Southern Randonnee), so I had the time to ride. While working full time, I've only ever managed just slightly over 10,000 km in a year, for several years.