It’s not much written about, and, yes, it sounds as silly from here as any other ‘war’ fought in any other industry (looking at you, Pepsi v. Coke), but in the middle of the 20th Century, there was, in mechanical watches, a jewel war.
At the time, there was a far wider variety of options regarding jewels in movements, from simple no- or 1-jewel movements (especially common in kids’ watches) to 7-jewel movements to your expected 17/23/25-jewel movements. To some degree, jewel count in mechanical movements was understood, perhaps akin to like horsepower in cars, or the number of LEDs in a red-light mask, i.e., more was better (even if that wasn’t and isn’t always the case).