jbd, good for you. This "life support" bit is a mystical term to intimidate the uninitiated and make the SCUBA industry priests feel more important, lock up trade, and charge higher rates. Already, they hang out shingles like physicians and lawyers. Heck, people used to build their own diving sets and other gear from surplus parts, and they were respected for it. Now you can't even buy a maintenance parts kit for some brands, even at inflated prices, and told that you are a fool for trying. This nonsense has even spread to charter boats where some captains specify which gear configuration is "approved".
It's all part of the transformation of a resourceful frontier people into a sickly, risk averse and regimented society.