"Skilled cyclists use the front brake alone probably 95% of the time. This is incorrect."
I've read that something like 80% of the braking capacity is in the front tire- as the rear lifts & skids under heavy braking.
But then I'll see statements that 80% of the braking that is done is with the front tire. I think that is likely an incorrect interpretation of the capacity statement. Unless people just choose to brake mostly with the front, or unless they routinely brake so hard they are forever skidding the rear tire.
On something like a long slope, where you need prolonged braking but not hard braking, the capacity of the two brakes should be about equal, based on heating, rather than skidding.