I've always found that cringe to be a strange shibboleth. AFAICT everyone has to summarize with the bay area instead, which I find even more comic having grown up on a coast, aka a bay area.
I'm not sure why it's a strange shibboleth? Not every name has to be shortened, and if you are going to shorten names, not every short form is acceptable. I don't know where "San Fran" came from, any more than "Cali", neither of which are used by locals, but it just doesn't feel respectable. It's not the name of the city.
Your words ... 8)
My first name is Jonathan, I generally get referred to as (int al) Jon, Jonny, Jo, or John (bloody silent letters).
As it turns out, until I was 20 I thought my name was spelt Jonathon. I got a copy of my birth cert to get a student loan and discovered the "truth" - even my passport was wrong and my parents had to sort out the first few of those and they should have known better! I was born in 1970 and no one noticed that I misspelt my own first name for 20 years.
https://www.sfstairways.com/stairways/eugenia-avenue-prospec...
Funny enough, though, it wasn't until I moved here 15+ years ago that it struck me how odd it is to call it "the Bay Area" and expect people to know what that means. Nonetheless, sportscasters do it. Musicians do it. All other bay areas are just areas around bays...
excuuuuuuse you? It's "drive on 101" in NorCal :P
But shortening San Francisco to San Fran is both very obvious, and betrays a cheap attempt at sophistication that the soul of SF rejects.
SF feels like a transitory city as multiple successive waves of people drift in and out. That also contribute to why a shibboleth like this gets a lot of airtime. The episode probably recurs weekly in bars all over the city as someone who's just moved here calls it "San Fran", only to be corrected by someone who's been here for just a little longer.