Good point, I didn't know that!Solutions to risks are based on reasonable probability of that risk happening. Vessels have twice the capacity of lifeboats incase there is a problem with some of them. They are also maintained and inspected to ensure a high probability of availability. Additionally it is a legal obligation, globally, that crews drill to ensure response times are adequate. Therefore there is an expectation that emergency response processes and equipment will do what it is supposed to do when required. Now, all this may or may not happen depending on the level of inaptitude of the company that runs the vessel and the master that commands the vessel, nevertheless, control activities are in place to ensure performance times and outcomes for emergency response are achievable.
What you are doing is applying multiple failure modes one after the other, irrespective of probability, when in fact the probability of that even happening is so small as to be irrelevant. If one of these improbable events happen and people die the courts decide who was at fault. Actuaries price your life at around $2million, if the cost of controls to keep you alive exceeds that, you can die and insurers can pay out. For example, do you expect a ship to be protected against a meteor impact, as that is the level of absurdity where such approaches end up.
Regarding survival suits, some ferries do have them for passengers as well as cruise ships based on risk assessment. Some information below on the framework that control risks: -
Types of Life-Saving Equipment Onboard Ships
Floating about an environment that does not support human life is a dangerous activity that carries a degree of risk of death if it all goes wrong, you can't run away and hide at sea. If you are planning a cruise in cold waters, then ask the company what safety controls they have in place and whether your safety can be assured to a risk that is ALARP - they will know what you mean if use the term ALARP. Then make the call on whether you should stay on land or go to sea.
Fair point that crew who might accidentally end up in water have one though. Of course I don't expect such protection. Maybe I could invest in my own passenger (not crew) survival suit, put it in my backpack, and wear that at all times on a boat if I'm that paranoid. That way I'll be able to put that on after my lifejacket if I have time or deem it necessary e.g. in the event that it takes a while to get lifeboats and/or rafts ready, or they end up unavailable. Thanks.