Sidewalks being too narrow is an issue of prioritization. Cities have optimized for car traffic in many locations, and everyone else has to take the sliver of concrete they were graciously given next to the cars with one or two people in them each. You may think, but we can't make it wider else the cars don't fit. Absolutely. So don't let them there at all. Flank every block with a walking/slow bicycle/scooter/board plaza. City centers are for people doing things, so we should prioritize foot traffic, because if you are in a car you are merely coming to or moving through the city. You are not the primary use case of the city center. It evolved this way over time but that doesn't mean it was the right choice to let cars flow through city centers, and we can change it back.