regulators are not life support either, this is a lie propagated by the dive gear industry to sell more expensive regulators and restrict service materials. If your life really did depend on your regulator working, there would be many, many more dead divers and probably very, very few people would choose to dive. I certainly wouldn't. This is why things like air sharing, alternate air sources, even CESA are taught. Air is life support underwater, not your regulator. Any decent diver knows to always dive in such a way as to have access to air from at least two sources, the second source typically being a buddy or the surface in recreational diving. Regulators are pretty reliable, but they do fail from time to time.
This is pretty distorted view of what the regulator does and what it provides to the diver and a gross false accusation of the diving industry. You are throwing everything at the wall hoping something would stick here.
Redundancies and alternate plans for air delivery you mention are actually proof that the regulator is indeed a critical "life support" system without which the diver is in trouble. If the regulator's function weren't critical, we wouldn't bother with alternate plans.