We are so far away from living independently underwater that I'd say we're hundreds of years away, if it's possible at all. Energy production. Food, water, air

We are so far away from living independently underwater that I'd say we're hundreds of years away, if it's possible at all. Energy production. Food, water, air. Resources. Mining. Industry. The harsh environment (salt water, fouling et al.) Even "gravity" (as in, if you drop something underwater, some of it goes up ...)