All of those San Francisco mobsters had very limited police records, especially if they didn't get out of the city of San Francisco often. SFPD was not interested in locking them up for some reason.
And by the same token SF never had the pervasive variety of illegal rackets available to run like guys did in other cities. Originally bootlegging, some gambling and some drug distribution, etc. That was mostly it. So because of less racket activity there were less arrests on their records. A second reason I think is also because many of them were already older (very similar to what happened in San Jose) and by the late 1940s into the 1950s and later many were no longer interested in 'street rackets' per se. They were either semi-retired or operated small legal businesses they had started.
So with few exceptions you just didn't have the same type mentality or member as guys in other states.
