> menus don’t seem to have drastically changed over the past 175ish

After looking at a dozen of the ones from the Boston area I have to say that my sampling disagrees with yours.

Turtle, Sweetbreads, Venison, Mutton are all things that would get a foodie OUT to eat today and seem to have been much more common then.

Also much of what I am seeing as "boiled" is going to range from "poached" (salmon) to "braised" (some of the tougher organ meats). Stumbling across a "boiled" chicken, served with rice and cucumbers in an 1800's menu made me jump to "Hainanese chicken rice". That preparation seems exotic to the modern American style but might not be as alien 100 years ago (Flavoring aside).