> But what if busses operated on their own dedicated network?

But if you're building a dedicated network in a major city, why on earth would you limit it to buses? Even with a dedicated network, I don't believe buses can be as fast, comfortable or quiet as rail.

I spent a lot of time in Melbourne, Australia and the trams there are fantastic. You can barely hear them when they're operating so they do a lot to decrease noise, they have a ton of standing room and are quite long, so they can carry a lot of people and I don't believe a bus can come close to the comfort of rail.