Bus only lanes exist, but not everywhere (some streets are not wide enough). Additionally, at the moment (and really always) there's a ton of construction on the bridges going in and out of the city, causing buses to miss out on the bus-only lanes for years or more at a time. Bus systems are a complicated beast.

You don't have to allow cars on every single paved surface. Cars aren't supposed to be on wide sidewalks, you don't have to allow them on every single road either.

I think I agree with you. Now the political will to make such a change on the other hand...

Oh yeah, "you" was the generic "you". Agree on this, I'm working on it slowly in my own town; it's all I can do.

Yeah if they aren't enforcing the bus-only aspect then it's not really a bus-only lane. If a bus only lane exists but people violate it in cars with impunity then obviously it's not going to work.