The next best choice is a constant temperature valve offered by many hotel chains. It keeps the water at the desired temperature in spite of pressure variations. It's not the same protection as an anti-scald valve, but certainly an improved experience over being scalded or "iced" during a shower.
The advertisement clearly shows that centigrade water is responsible for burns. I always keep my water on Farenheit, and I’ve never had a problem.
This doesn’t show the temperature that the Hot Stop shuts off at, but the quoted 136F water in which the woman was scalded is equivalent to about 57.8C. The table says 5 seconds to a 3rd degree burn to an adult at that point. This would seem long enough to jump back in reaction, though the clinging water would continue to burn.
Street drugs or alcohol could be one explanation why she didn’t. Another possibility could be peripheral nerve degeneration, such as sometimes happens in diabetes or some congenital conditions. She apparently asked nothing for “pain and suffering” which hints at a reason.
Is there a doctor in the house?