Originally Posted by
BFSGrad
The technology for such expansion is well established; e.g., HNL reef runway, Hong Kong, Chubu, etc. Plans for this type of expansion at SFO were floated in the 90s with the #1 obstacle being environmental groups. If the bay area governments can toss a couple $B at new sports stadiums, they can certainly pony up some dollars for a new SFO runway. What is lacking is the political will to buck the greenies.
Bucking the greenies and other environmental groups is expensive - usually extremely expensive, and getting the needed environmental plans and permissions often takes decades - and even once approved, you can usually count on numerous more lawsuits and challenges - all of which cost time and money. Filling in sensitive wetlands to create new land has become an environmental mine field. This being the California Bay Area means the environment groups have outsized influence.
Concerns over tiny fish most people have never heard of have already shut down $billions in agricultural output by limiting the water available to grow food. Increasing the footprint of SFO so more carbon spewing aircraft can land in there is going to be a political nightmare in hugely 'progressive' California.