On the Misnomerhood of “Total Immersion”

I’ve heard that one of the quickest ways to learn a new language is total immersion. I agree, though my definition is likely different. How many native speakers do you think exist in an environment of TOTAL IMMERSION? Not many, I’d wager. Most people don’t immerse themselves, or even think about language much at all. Most people merely learn what they need to to get by (if that) and then stop there. Tell me, how is this total immersion?