Compare it to e.g. the nearby San Jose - SF is so much better that it's not even funny. What US city would you consider more "walkable"/ tourist friendly? MAYBE NY, if we only include Manhattan and nothing else.
For a week or so tourism SF, Manhattan, Seattle downtown, Boston. Cities I can think to not be very walkable are LA and DC perhaps.
What are you talking about? The first time I visited SF I just stumbled upon Haight-Ashbury and Japantown by walking around.
Yep, NYC is not very walkable if you leave Manhattan island. One big difference though with NYC is the naming and the political boundaries. NYC is very unique in America because it's one really big city with different "boroughs", all very different from each other. If it were any city, it wouldn't be like this: all those places would actually be separate cities, all part of the same metro area. (NYC has this too, with Jersey City, Newark, Stamford, etc. all being part of the metro area, but it's remarkable that so much of the metro area is actually one city.) Just look at LA for instance: LA itself is a pretty small part of the metro area, with many other towns and cities comprising it.