What's the issue getting to San Francisco? There's a bus linking the Texas Eagle to the California Zephyr. And Emeryville is only 7 miles from San Francisco, with full-service buses including checked-in baggage to the San Francisco Ferry Building.
Read the OP's post carefully again. He is mentioning about inconvenience in reaching San Francisco
from Dallas, which is valid and true. To go from Dallas to SF, you have to first go down to San Antonio, connect to a train that runs only three times a week to Los angeles, and then ride up the coast to Bay Area. If you happen to be traveling on a day when the Sunset does not run, then you have the ridiculous routing of having to go first to Chicago, and then ride the California Zephyr to Emeryville.
There are a couple of important "missing links" in the network in the center of the country, and the OP is right in pointing it out. An extension of Heartland Flyer to connect to Kansas and Omaha would provide Texas and Oklahoma connections to Chief and Zephyr to travel west without having to backtrack to Chicago. But as we all know, that's only something we can dream of. Not gonna happen.