As it turns out it doesn’t actually cost that much on regular transit, there’s an AIRPORT SURCHARGE because it’s an “airport train”.
No wonder Americans don’t use public transit, even when the system exists it’s ridiculously difficult and expensive to use.
As a counterpoint here is mine
Except way off peak it’s faster to take bart than drive (north berkeley to downtown SF). I usually take a trans bay bus when going to office (closer to my house) which is $6 one way. BART is like $8. (So round trip under $20). Vs driving is $8 for the bay bridge and then somewhere between $20 and $60 to park for the day (no free parking at my office).