I think the definition of walkable often comes down to whether people are willing to walk there. If you walk 10 blocks on maintained sidewalks past a variety of storefronts, office and residential entrances-- a lot of visual interest, and there are shade trees with surface landscaping, then that's probably a place people will walk some distance without complaint.
https://www.google.com/maps/@39.0864845 ... 6656?hl=en
If you walk 10 blocks on cracked sidewalks past surface parking lots and hostile, block-long parking garage facades, then most people probably won't walk there.
https://www.google.com/maps/@39.1019008 ... 384!8i8192
When I lived on Quality Hill, I often walked from 10th and Washington to the former public library at 12th and McGee. I had a couple of routes I followed that was more aesthetically pleasant than the other routes at that time (pre-P&L). I rarely diverged from those routes.
When I lived in NYC, I regularly walked 10-15 blocks to go somewhere. I never noticed because almost every route was well-maintained and had enough visual interest to distract me from the fact I was walking. If I had to walk the same distance down Metcalf Avenue, I would drive a car.