> The UCI requires a minimum wheel size of 55 cm, yet racers use 700C wheels that are 10 cm larger than required. If wheel weight mattered as much as most cyclists imagine, then pros using the smallest wheels would win every race. And yet, even though many have tried smaller wheels, all have returned to 700C wheels – probably because the larger wheels handle better due to their optimized rotational inertia. (But that is a topic for another post.)

I know this! The answer is because the neutral van only carries 700c wheels. If a rider gets a flat the wheel needs to be replaced quickly thus it's advantageous to use the most common wheel type. It is explained in this video by a professional cyclist: https://www.youtube.com/watch?v=jLnwR0ZxhcI

Wider tires are discussed in this video (also by GCN): https://www.youtube.com/watch?v=yrHxQg1OW0A They also find that wider tires are slightly faster. Although they discuss widths of 23 vs 25 or 28 mm which seem like a minor difference for most cyclists. But probably makes a world of difference for professionals.