Huh? Of course it doesn't: neither Texas nor California have routes that would be economical for an Acela-like service. LA-SD is a single point-to-point route; neither LA nor SD connect economically with any other California city.
I also don't understand your "peak versus average" speed thing. You're comparing apples-oranges, not me: I'm comparing peak-to-peak. Normal Amtrak trains also don't average 75MPH!