SF voters are largely not techies. People who vote tend to be boomers or older, and organized (union, other political types, more organized or regulated industries). Techies tend to be younger, more transient, often non citizens, etc, so not a great voting bloc, even in SF.

Her district, CA-12, is SF City and County proper; there are probably only 50k techies by any definition in a city of around 800k. I'd estimate around 10-15k voters. Out of that group you probably have a higher than usual number of libertarian or green or other third-party voters too; probably far fewer party-line Democrats.