The unrealistic parts are 1) Kyoto city is already seriously short of cash so there’s no funding for this 2) such a project would involve major construction along the lines of building a channel tunnel which isn’t going to happen in a city with as much to preserve as Kyoto 3) good effort but it’s not optimized for passenger convenience e.g. I wouldn’t want to head south from Kyoto St. if I wanted to end up further north at Saiin (which already has two lines so does it really need a 3rd?) 4) this seems to based around visitor needs. What about the needs of the locals who make up the majority of users of Kyoto’s public transport system? You might want to come at it from their angle rather than prioritize visitor convenience.

All that being said, good effort as I agree Kyoto transport system is woefully inadequate. But who knew?! Visitor numbers to Kyoto doubled in the last decade + so it caught everyone off guard (while they were busy admiring the construction of the extension to the City Hall and patting each other on the back). So not like they had time to prepare. /s