nah, nobody gives a shit about service and amenities. You choose the train that goes where you need to go fastest, that's the only thing that matters. Agencies coordinate with each other to build complementary lines. Nobody chooses to use a train because it's run by Toei vs JR, and train lines generally do not overlap.
Leasing infrastructure sounds alright tho
in capital intensive infrastructure businesses like rail travel and telecom, it actually makes sense for the government to provide the high upfront capital to build the common infrastructure and lease it to the competitors (but not sell or give it away) to create viable markets like this.