The Tesla factory has a BART station and a mainline rail station, so that's good. But the Tesla office is way out in the middle of nowhere.

https://www.google.com/maps/place/3500+Deer+Creek+Rd,+Palo+A...

The Bay Area's public transit is only good compared to places with no public transit. It's far from comprehensive and the intermodal coordination is pretty non-existent. It's only good if your start and destination are on the same mode of transit.

I don't know about Austin, but with Fremont's public transit, it would take at least 40 minutes to get from the Fremont BART station to the Tesla factory on public transit. That doesn't count the time needed on BART from someplace with a lower COL (Fremont itself is a $$ place to live). For that, add at least another 1/2 hour (for nearest lower COL in Castro Valley or San Leandro). So, it wouldn't be unheard of to have an hour+ commute to Tesla Fremont on public transit.

Large and wealthy Bay Area employers like Tesla therefore run private shuttles for employees for this reason (a practice started in the current era by Genentech way back in the early 00s I think, and later Google popularized it among tech co's)

Maybe Austin has world class public transit, though I kind of doubt it.

Why would anyone use Fremont BART when Warm Springs BART almost abuts the Tesla factory?

Fair, but it's still 27 minutes from there to the factory on public transit, so not quite "abuts". I know you can take the company shuttle, but the point is that the public transit system isn't very practical end to end.

I actually would give Tesla a bit of a pass on this since it is a factory purchased from GM/Toyota and it inherently needs lots of space, so you can't expect a train station at the factory gate.

Tech campuses like the Googleplex, the Apple spaceship donut, Oracle HQ on the edge of a marsh are where the failings of the public transit system are most apparent.

There's a footbridge from the BART station to the Tesla site. I don't know why someone would waste their time trying to take public transit from the station to Tesla. It's 1-2km depending on which side of their gigantic facility a person needs to reach.