VO2 max is just one of the parameters for evaluating the performance abilities of a cyclist.
Others include lactate threshhold, max power output, power to weight ratio, bike handling ability, teamwork, nutrition, hydration, motivation, pain tolerance, equipment selection, aerodynamics, recovery rate, mitochondrial density, resistance to disease, blood pH, and probably some others I have forgoteen or neglected to mention.
If VO2 max were everything, then racers could just lne up and perform a lab test to determine the winner. But, that would be boring and limiting.
So, the racers race and everything comes together for the best rider on that day on that course and a champion is crowned.