What might be instructive for some here would be to analyse the power files of tour racers. They are not always at 90-110 rpm. Look specially when the peloton is not strung out, those in the pack tend to have lower cadences and low power (for them). Just because Pros tend to spin doesn't mean it makes sense for all of us all of the time. Case in point, the 24H world record is about 640 miles or 27 mph moving. The fellow did about 280 watts with a cadence of 78. I reckon he knows his cadence.
The appropriate cadence for any rider depends on many factors, most of which are physiological.
For my needs, efficiency and fatigue drive my cadence decisions. Higher contractile forces engage fast twitch fibers. These motor units fatigue quicker but they also use less O2 compared to the slower twitch fat burning units. At lower cadence, the inertia of fat legs is less. My preferred cadence varies greatly depending on power output and also on crank length. I've churned 200mm and spun 150mm over the years.
Professionals are a bit different than most of us here, certainly me. They have to spare glycogen for the finish or key moves and for tomorrow's race. Higher cadence (it is really a peak torque thing) engages more ST and generally using beta oxidation (fat) relatively sparing glycogen compared to a lower cadence/higher farce combination although the higher cadence requires more O2 due to higher cost to oxidize fatty acids and then there is the problem of my fat legs going faster. And the Pros make a lot more power.
Just buy a near-infrared spectroscopy device like a Moxy, lactate meter, HRM, and PM. It isn't hard to figure out.