How short is short? Edinburgh looks pretty small. I just plotted a route from a random point in the center to a place called Bonaly that looks like a residential area, 5 miles away. Two observations is that traffic is pretty bad (red), so it looks like people drive even though transit is available, probably confirming my prior observation that people will choose to drive until driving capacity is used up or over-used then switch to other modes. 2nd is that transit will take 43 minutes vs 25mins of driving (and that doesn't account for waiting time, nobody has exactly perfect timing), so driving is still faster :)

As for cars it's actually one of the biggest things I changed my mind on in my life. I used to be anti-car and always lived in walkable areas till my mid/late twenties. Then I actually tried driving and living in non walkable areas and I couldn't believe how wrong I was :) Especially when I go back to visit walkable areas and it's annoying and getting anywhere takes forever, something I never noticed when I lived there because it was the default.