It might fly if you fly. :-) I don't know if this is still true, but when I lived in Silicon Valley a little over 20 years ago, I did some price comparisons, and it worked out that for the cost of a nice SV house, you could buy a much bigger house and pool in the Merced area in the Central Valley, and a Mooney M20 (private plane with a cruise speed of over 250 mph), hanger space for the plane in Merced and Palo Alto, and a car to keep in Palo Alto. You could even get the house on enough land with room from a runway, to save having to drive to the Merced airport every day. Get a couple other people to move to Merced and share the commute to split operating costs of the Mooney, and it looked like this would actually be quite viable.
Except my half of the Berkeley two-on-a-lot cost substantially more than $750k...
Welcome to the neighborhood! :)
You can't live comfortably in SF proper on less than $120K-150K/year.
If you network and land in a rent controlled apartment (a friend of a friend has the 4th floor of a mansion in the haight for $900/month) you can do it for even less.
A 1-bedroom in a building next door to the Mission Hotel - San Francisco's biggest SRO hotel, located in the Mission District - just went for $2800/mo.
And the building isn't rent controlled.
I was talking about places like Sunset or Ingleside--not highly desirable, but not Hunters Point or the Bayview.