My personal experience of the multiple operators in Tokyo while traveling there only once for tourism was that it is a mess and not very convenient for users. Like having a station with almost a same name but different operator, a few hundred meters or a km away. And the difficulty of commuting between lines.
Confusing, perhaps. Inconvenient, not really, the same Suica/Pasmo cards work everywhere and handle transfers seamlessly.
Yeah, if a tourist refuses to have a Suica/Pasmo card, they're going to be quite inconvenienced.
Also, Mt. Fuji Station and Fuji Station are 2h30m apart: https://www.google.com/maps/dir/Mt.Fuji+Station,+2+Chome-5-1...