Honestly, this hobby is really not doing a good service to the nature. Although its right IMO our hobby doesn't cause that vast or big dmg to the coral, but its still damage being done nevertheless.
These water-borne life forms should be live in the ocean, even their habitat is degrading. But nature have a responsive system by themself. Within their natural habitat, the life forms --may--l adjust to new environment chgs, its called evolution.
Keeping them in our tank, that's not --saving-- their life act at the best.
With the lifeforms gone in the world, and with your pets living crazy happyily on your tank won't --revive-- the population in the nature anymore.
Extinct doesn't mean when the lifeform is downed to zero.
Life form considered extinct when the remaining # can no longer sustain a positive growing\stable population in the open for coming generations.