Well, nobody relies heavily on trains for their commute in this region because the train hasn’t been built yet.
Also, a vast majority of the people who work in agriculture aren’t “farmers” who walk out of their house and till their own land. They are laborers, who often live far away from their work sites, which shift with the seasons.
There are stops between those two places and “grape pickers” as you call them (though they do much more) also… do other things besides work. In fact, HSR will enable them to do those other things even more.
It will also allow people in those places to work other jobs besides “grape picking.”
Well, how about living in Merced and working in SF area? If a trip from Merced to SF would be less than 70mins, this would beat all rush-hour traffic along 101, and become viable living option.
Until gen z gets their polyculture garden cities with a large variety of crops for each season, I don't see that changing