Cadence is Learned!
If it makes any difference to anyone, spinning a higher cadence (85 or higher) is a "learned" activity. For newcomers, don't be too concerned to see your cadence in the 75-85 range. Even experienced riders have to relearn spinning at higher cadences occassionally.
My brother has been riding for 10 plus years and takes a different winter training regime than I do. My brother is a stronger overall rider than I am in terms of speed and climbing ability. Maybe being 12 years younger helps as well. His approach is to ride less (less than 200/month) and do weight lifting. He really improves his overall strength doing this but loses some aerobics during that period of time. My approach has been to continue to ride as much as I can. In fact I averaged 500-600 miles over the winter months doing the weekly centuries at slow speeds. By summer, his overall conditioning will probably be better than mine.
When he started back to increasing his mileage he had real difficulties spinning at his old normal higher rates. Thus, he concentrated for several weeks on spinning at higher cadences and now has that tuned back up. So, even for someone that has more than 50,000 miles in the saddle sometimes they have to relearn some activities.
By the way, I just beat his personal record at the last Time Trials by 5 seconds!! So, we continue to challenge each other and push each other using different methods. Which one is best? Probably whichever one the person really applies themself to.