> We usually don’t bathe every day and listen to our body’s needs. If I did this I'd need to shower every 4h :)
This helps you to live with a healthy skin microbiome that is effective at maintaining itself. I can easily skip a shower for a day and be fine, because the buggies living on my skin help manage the population of bacteria and yeasts that ultimately contribute to smells, pleasant or otherwise.
However the transition from Western-style harmful hygiene practices (harsh soaps, extreme obsession) back to a more normal baseline can take a while, and requires being a little gross as your body re-learns to manage itself without such drastic outside measures as strong surfactants.
tl;dr your skin and scalp easily develop an unhealthy dependence on external soaps, resulting in a chronic inability to manage skin microbe populations, which means you're covered in uncontrolled colonies of stinky microbes until your next shower. Let your body handle it and it will manage those populations itself.