another big bump in life modern expectancy was discovery of antibiotics, which does tie back into hygiene.
soaps in general are emollients, they work to help the water wash away the dirt and particles that are in your skin/hair oils, because that oil is hydrophobic so water alone is fairly ineffective. some soaps also have additional ingredients, like moisturizer or antimicrobials.
but what that means is, different people will have different needs for various soaps depending on their bodies, which parts on their bodies, and what kind of things they do with those parts (before or after cleaning).
antimicrobial stuff is obviously important when you're worried about germs, but it's also good to use on any of your dark, dank, moist spots because most body odors are actually caused by bacteria (including bad breath). it's also good to scrub those parts good, because the bacteria can hang out, or be situated in a layer of cells or grime (like how brushing is better than just using mouthwash).
I do agree that some people are very afraid of normal body odors & it can be horrible for you. decades of advertising & media have a lot of people with vaginas thinking there's something wrong with them if it smells like a vagina, or doesn't smell like perfume. and, just as with the previously described cycle of over-shampooing and oil production, they use products that over-clean and fuck up their microbiome which causes overgrowth - in this case, they're usually killing off the beneficial bacteria that keep the bad bacteria in check & they end up with BV or a yeast infection, which makes them have more odors & discharge, so they use more products, etc.