Grossly over-simplified argument. A lot of that open land along 280 for example is watershed for public drinking water. There are two ways to solve said housing shortage: build more housing or PAY people more money to afford what is there.
I do not think it is overly simplified. You cannot have your cake and eat it too.
The Presidio and other lands become available and they choose a park. Other land is set aside as open space. You may not build multi story buildings to preserve the sky line/view. Impact fees and permitting costs tens of thousands for modest structure to hundreds of thousands for large structures.
It is this way all up and down CA’s coast. It is what drives the cost.
Thoreau said we are wealthy in proportion to what we can leave alone. If you are a multimillionaire you can afford a Presidio park but most of us cannot. As he noted, Reagan said the solution is simple but the choices are hard.
There is no “housing shortage”. If there was a shortage, construction would be up, because nothing drives up prices (and therefore profits for builders) like a shortage.