It’s really best to go to The Guardian where the interactive graphic below appears, but, as you can discern from the general direction of the data, the nation’s State of the Union Addresses have been “dumbed down” quite a bit over the last two-and-a-half centuries, Jimmy Carter’s 1981 address being a notable exception.
Of course, much of this is a result of writing styles having changes rather dramatically over time and the fact that in the late 18th and early 19th century, politicians weren’t trying to appeal to everybody as much as they are today. For example, here’s an excerpt from James Madison’s 1815 Seventh Annual Message that surpassed all other addresses in the graphic above.
It is another source of satisfaction that the treaty of peace with Great Britain has been succeeded by a convention on the subject of commerce concluded by the plenipotentiaries of the two countries. In this result a disposition is manifested on the part of that nation corresponding with the disposition of the United States, which it may be hoped will be improved into liberal arrangements on other subjects on which the parties have mutual interests, or which might endanger their future harmony. Congress will decide on the expediency of promoting such a sequel by giving effect to the measure of confining the American navigation to American sea men – a measure which, at the same time that it might have that conciliatory tendency, would have the further advantage of increasing the independence of our navigation and the resources for our maritime defense.
Aside from their eyes glazing over, I don’t know how people would react to something like this today.