I’m not surprised. I forget when I looked up the research, but several hair typed definitely don’t need shampoo as much as people think they do. That we have another product (conditioner) yo undo the damage shampoo does to out hair is astounding.
As for the overall bathing thing, I agree. It depends on what you do day to day, your environment, and genetics. With all three of those factors, some people need to bath more often than others need to.
Most of my washing routine is actually for chronic pain. I don’t need to scrub for smell too much, but hot water feels good on pained areas.
Sounds like you have a lot in common with my father's reading tastes. In which case, I will recommend the Thursday Next series by Jasper Fforde.