Infrastructure refers to roads, water supply, sewers, power grids, telecommunications, and the like. So you want states fixing the INTERSTATE highway system? What might THAT look like? You want states determining water supply without any national coordination? States having all their own separate power grids? States setting up their own telecommunications networks?

The interstate highway system built under president Eisenhower was what turned America into an economic superpower. Even the most libertarian of economists acknowledge the need for national infrastructure and the federal government's economies of scale to make it happen.