Capex for countries isn't really that big of a problem. You can raise lots of capital for long term, a proper investment should increase land values (or property values).

Generally societies that invest a lot of capex in high capacity transit do quite well.

Also roads have high capex along with operation cost, along with high private cost. Not even mention the additional cost for health and other hidden costs.

If you go by total lift-time cost by capacity then its a fantastic deal.