The first argument is BS as you have no idea what a non-existing service would be priced at. Your second argument on the other hand rings true and is the main

The first argument is BS as you have no idea what a non-existing service would be priced at. Your second argument on the other hand rings true and is the main reason high speed train service in the US makes less sense. Many cities have near-zero infrastructure locally to transport passengers to their final destination. Same goes for airports too though. It's very different for Paris - London where both cities have excellent subway networks or Tokyo - Osaka (ditto) or anywhere within China. The Taiwan HSR is also very successful since it got better connected to local trains including Taoyuan airport.