in short: you're (incorrectly) extrapolating what you know about one midsized city to the rest of the US.
Maybe somewhere like Portland is different; I haven't been there.
It's like living in rural Idaho then complaining that America needs to learn how to pave roads because packed dirt just isn't cutting it.
As a pedestrian you don't need to "share the road", only to cross it. Sidewalks seem plentiful, even if underutilized, and most road crossings have been well marked and signaled. Cars have generally been respectful when I cross.
Cycling here would certainly make me more nervous, outside of the corridors with well-spaced dedicated bike lanes. But walking is fine. It's good exercise and the weather's great.
I am willing to bet very few drivers will stop for you at an unmarked crosswalk, as well.