I'm not a materials expert but I think it's more the butting rather than the alloying that raises the price of steel for bicycle use. Nonprecious metals are exactly that: nonprecious –i.e., relatively cheap. About the only nonprecious metal that isn't cheap is titanium and its relatively high cost for bicycle use comes more from the work it takes to make flawless tubes with it and not the cost of the materials.