The only time I've come close to 7,000 miles was when I bike commuted. That was about 4,000 miles per year of "free cycling" and the other 3,000 miles was one long ride per week, an occasional second shorter ride, and often a high mileage biking week on family vacation.
I'm still working but work at home - no commute! That does give me flexibility to work in an occasional mid-week ride but a high mileage year (like 2019) is now about 5000 miles for me and that includes about 1,500 mile on my bike indoors on a smart trainer and Zwift. Between work demands, family demands and weather, I'm happy hitting 3,000 outdoor miles any year.
I don't see that changing much when I retire - I enjoy hiking, kayaking and another recreational hobbies that demand time, too.
It is a pretty simple equation, there are only 3 variables: (1) Ride faster (higher mph/less stop time); (2) Do more rides that require less travel time to the ride; (3) Stop doing something else and ride more hours!
I ride to maximize fun. Faster is more fun sometimes, not all the time. Traveling to interesting rides is often a lot of fun. Other things than biking are often more fun than biking! I have a friend (not a racer) where pretty much all the fun is faster and he doesn't have any other daytime hobbies and he mostly does the same routes from his house all day long - he is one of those 7000+ miles per year types and loves it.