Why is Shinkansen so expensive in Japan?

I've always wondered, why is the Shinkansen, Japan's famous high-speed rail system, so expensive compared to other modes of transportation? Is it due to the advanced technology and engineering that goes into building and maintaining these trains? Or is it the cost of the land and infrastructure required to support such a vast network? I'm curious to know if the price reflects the level of comfort and convenience that passengers experience, or if there are other factors at play. Could you provide some insight into the reasons behind the Shinkansen's high cost?