An Acela-like train probably wouldn't be that fast. On the Northeast Corridor, the Acela is only around an hour faster than the regional and part of that is just making fewer stops. My guess is you'd still be looking at 7+ hours in CA, at which point most people would just fly.
(Very few people actually take the Northeast Corridor from Boston to DC because it's pretty much a full-day trip. But New York is in about the middle so there are two popular sub-sections--unlike the case with CA.)
The Acela is only that slow because the rail infrastructure can't support the maximum speed of the train's rolling stock. The purchase of the rolling stock was supposed to spur the redevelopment of the tracks, but that never happened.
My comment was mostly in the vein of wondering what a "cheap" (relatively) not-really HSR could have looked like and the answer is probably "not fast enough to get from Emeryville to LA in a timeframe where people would really use it."
And, of course, the rolling stock had various problems so I'm not sure what the theoretical top speed ended up being.
(Very few people actually take the Northeast Corridor from Boston to DC because it's pretty much a full-day trip. But New York is in about the middle so there are two popular sub-sections--unlike the case with CA.)