I’ve always thought there’s a lot more gold in vaults than admitted to.
I know an underground miner whose last job before the mine was closed was to mine out a stole of visible gold nuggets and leave it there in the chute ready to be loaded.
That mine shaft was since retimbered and could be reopened quickly.
Who knows how many other lodes are there waiting to be brought up.
Mines pay no taxes on Minerals in the ground.
As to mining asteroids, as with any announcement of high tech esp relating to national security, they don’t say it unless they’ve been doing it for decades and they have something better their keeping secret.