Unless you count gas-taxes re-appripiated for mass-transit as a 'profit'.
Most of the Interstate is supported by fuel taxes. Fuel taxes are paid for by drivers. Who use the Interstate. So, I'd say that it's a pretty good case of 'user pays'.
Your argument would work if the fuel taxes funded the construction and maintenance of the interstates. They don't. If we wanted them to, we could get there without raising the fuel taxes paid by passenger vehicles, in fact those might possibly be reduced (though the reductions should probably be replaced with carbon taxes, used to fund carbon sequestration). Taxes on the fuel (or whatever) paid by trucks, however, should increase several fold, since they cause the vast majority of the highway construction and maintenance costs.
I really wish we'd fix up our highway funding so that it is usage supported, ending the massive subsidy we give the trucking system. Doing that would cause most of our bulk freight to move from the highways to rail, which is more energy-efficient and would make passenger highway travel safer. Unfortunately, it would also cost a lot of jobs in the trucking industry which wouldn't be offset by jobs in the more manpower-efficient rail industry, and that makes it politically impossible.