There are no famous roller-bladers. Bladers don't pass bicyclists, laughing at how slow they are. If a blader and a bicyclist run into each other, the blader will be hurt more. Poor kids in Africa, don't want roller-blades. Nobody born before 1985 ever asked their parents for roller-blades for Christmas.
Bikes come in more colors.
Can't roller-blade in snow. Can't ride roller-blades on the beach. Bikes have front and rear brakes. Never seen a car with roller-blades strapped to it's roof. Nobody ever rode a bike to disco music.