These things are self-reinforcing because as things stand bikes can't be used for commuting by most people because the infrastructure doesn't exist. Make it easier and safer to bike, and you'll see the demographics shift.

Another part of this problem is affordable housing. People can't live close to where they work. Reduce this problem along with improving biking infrastructure and you'll see an uptick in biking.

"Several businesses along Valencia Street have posted signs in their windows that read[...]"

Sure. Several businesses said the same thing about protected bus lanes, but studies have shown it's increased business for those on the path, because it makes it possible for _more_ customers to actually access their businesses.

Cars are fundamentally worse than public transportation or biking for small businesses as a whole, as they reduce density, and further consolidation, which favors larger businesses and hurts small businesses. The problem is that business owners tend to be drivers and their biases don't line up with reality, which is why you tend to see their personal politics interfere with their business interests.