there is a cacao bean bank. it won't become extinct due to a lack of the ability to cultivate.
although, changes to climate and extreme weather events will impact crops more often and therefore supply.
most companies also stockpile beans because of the delicate nature of growing cacao.
Cacao grows between +/- 16 deg latitude so a very tropical only crop and not in all areas. It does best when grown under the protection of other plants.
the stuff you guys seem to call chocolate is predominantly sourced from the Ivory Coast. The quality of the cacao used in the candy bars you mention in the posts here contain little in the way of quality cacao.
Not being a choc snob. It's just true. The crops that supply the big candy makers are designed to produce high yields with little in the way of quality or flavour.