No one is "rolling out of bed" to do this. I've got 6K miles in so far this the year, and there are a lot of guys here who ride a heckuva lot more than I do. I know people who will hit 25K miles this year. No s***.
And I never claimed (nor has anyone else, yet) that these speeds are sustained over Tour stage distances, or "day in, day out." We're talking about weekly racing training rides. Stuff in the 30-50 mile category. Big, big difference....
By way of background, I do a lot of ultra distance stuff and I ride with the racers (and started racing myself this season) to get some good speed work in so that I can crank up my rolling average. At the National 24-Hour Challenge this year, I rode with the leaders to the first checkpoint at 35 miles. My computer declared an average of 23.7mph, and that was on a rolling-to-hilly course and counts stops and starts at traffic lights, etc. Although that's a big number, keep in mind the leaders went on to ride more than 450 miles that day (I finished with 394). There are a lot of very fast nonprofessional (i.e., recreational, amateur, whatever) riders out there.