Or 35mph for 10 miles straight?

Ever watched a road race? It's usually not about beating someone over a 3 block stretch or up the hill to school. It's more about maintaining a higher average speed over many, many miles. You (collectively, not just bike manhattan), aren't thinking on a large enough scale here. Unless you're all exceptionally strong riders, a fit rider on a geared bike will beat you in a 50 mile race. It's almost guaranteed.