I don't know why you expect the mathematical order of operations to stay fresh in people's heads. I was taught that in like third grade, and the number of times I've needed that information outside of a math class in the 35 years since then is exactly zero. Most people don't really have occasion to go around solving written equations in their adult lives. I mean, I'm a machinist, I use math every day at my job, the only actual written equations I ever have to deal with are the ones I need to solve to shut off my alarm clock app in the morning. That stuff just doesn't stick when you never have a reason to use it.