From what I've read, while mac n cheese is considered an American staple, it was introduced to America by Thomas Jefferson after he had encountered it on trips to Europe.
It didn't become widely popular in the US until more than a century later in the Great Depression as it was a very cheap meal that contained both carbs and protein. Since then, it continued to be propelled by the marketing of low cost and convenience.
Even though we were relatively poor, I don't recall ever having it at home as a kid, but I loved when a friend's mother served it to us, the gooier the better. I do enjoy making a cheap little box of the stuff from time to time now, doctored up with some shredded chicken, diced celery, and Frank's hot sauce to make my version of Buffalo chicken mac n cheese.
My family has asked me to make a "real" version a few times, so I use America's Test Kitchen's stovetop recipe. It's super simple and you avoid that weird powdered cheese packet by using American cheese as the base for its emulsifying salts, but then stirring in shredded aged reserve cheddar, dijon, and cayenne for the flavor boost at the end.
Another trick is to boil tbe noodles in just enough milk so they become al dente, and the little remaining starchy liquid becomes the base for the cheesey sauce.
Some folks prefer a crunchy, toasted topping but baking will dry it out, so simply toasting panko in a neutral oil separately, then sprinkling over top of the mac n cheese makes it happen.