In our society where we generally use pricing to distribute limited goods, your desire to drive to and park at a train station, at no or low cost, is irrelevant next to the market price of that land when that price is about 6-10 million dollars per acre.
What you're asking for is a massive external regulatory subsidy in order to prevent the market from functioning, just because you like your car.
As a former BART station parking user: it’s not about liking your car, but your time. When you get used to a 10 minute drive, no one wants to switch to a 30 minute walk or 40 minute bus ride.
Point still stands, if you paid for the true cost of parking no one would bat an eye, but the current regime subsidized car use to an insane extent through inefficient land use policies. A true “market rate” bart parking spot would likely be many multiples above the current price when all costs, alternative uses, and competition are factored in.
AFAIK the private lot at West Oakland is still under $15. Well worth it. But yeah, the $3 BART charges is comically low. If it’s full by 7am, it’s too cheap!
You need to widen the universe of competition when you price parking. The universe of competition for an empty parking space is not just "everyone who would want to park here for a day" it is also "all alternative land uses to parking, including housing". A more profitable, and thus more efficient, use of the land would convert likely 99% of all BART parking land to apartments, retail and office space.
What you're asking for is a massive external regulatory subsidy in order to prevent the market from functioning, just because you like your car.