Nick, I have to agree with you. To me, the flotation is just to give me time to get out of the helicopter. Once I'm out, I'm still not happy - I've seen sharks the size of my helicopter swimming around out there, & everything in the water can swim better than I can. I'd far prefer something that kept me safe and dry so I didn't even have to think about floats.
But what is the cost? You can design in so much redundancy that the aircraft isn't economically viable, and no one can afford it. Consider that the vast majority of the aircraft operating in the US GOM are single-engine, the C+ costs us more to operate than a 214ST, and the S92 is likely to be so expensive I'll be surprised if 10 ever operate here. Somehow, the costs have to come down and the oil companies have to be convinced to spend some of the exhorbitant profits they're making. In the meantime we're hanging our a$$e$ out, and nobody seems to care.