I disagree.

Commercial manufacturing in space can be economically viable, as long as most of the components do not come from Earth.

If you build titanium stations in space, but all your titanium come from the moon, the price structure is wildly different. The price of shipping material is the price of building a railgun on the moon.

Absolutely not cheap,but the operating cost afterward is very low. And since the moon is geolocked, you can target any lagrange point with very good precision.

There will still be a need for components coming from earth, but the moon should be able to send all the material for structural parts (titanium), and also solar panels.