The title is a bit of an exaggeration.
Why do corporations change shampoo and toothbrushes so often? I’ll go through 10 different shampoos and toothbrushes, then find ones I like. I’ll probably be able to purchase them again a few times before the ones I like are no longer available.
What are the forces driving manufacturer’s to change their basic wares so often? Besides Wall St. greed, that is?
For creating more bullshit.
These products are actually good, and cannot be improved anymore (or maybe only a tiny little bit).
But competition is tough, and so they feel the need for strong advertising.
Advertising departments cannot do anything but lie in such a situation: They create stories that tell of constant improvement. Revolutionary change even. Ongoing research. More blades on your razor every year, and always 10 times sharper than before. Your teeth 10 times better than last year, and therefore the toothpaste needs this new color.
Exxageration because when they promise so unbelievably much, then you are going to believe just a little of it - where the truth is: there is nothing.