How do you take "a tiny fraction" away from a street that has one lane in each direction to build a dedicated bike lane? Make it a one-way street and just kill traffic? It's not as simple as you make it out to be. Don't infer motivations, I don't own a car and ride my bike everywhere.

It's mostly a money issue, at least where I live. That part of the budget is spent on "climate managers" (for a city of 20k) instead of improving bike infrastructure.