I bet 90% of them can't take a drink without wobbling all over the road.

This is just my observation as an ex-triathlete. When I was racing tris, I thought I knew how to ride a bike. Then I started road racing and realized I couldn't take a drink, put on or take off clothing, eat, hold a wheel, take a corner though the apex, get out of the saddle without shooting the bike back, bunnyhop, take contact, close a gap, recover at speed after a hard effort, echelon, pull through without causing a gap, read the wind, ride out a flat, execute a panic stop. The list goes on. These are all skills that are learned from riding in a group. I thought I knew how to ride a bike, but in reality all I knew how to do was pedal and point the bike in a general direction.