The recent political speeches at the economic clubs of Detroit and Chicago were a little deeper than Dick and Jane! Also 21 Nobel Prize economists found the content to be deep enough to disagree!
And heading in the direction of Dick and Jane doesn't mean that we ever reached it; according to https://community.jmp.com/t5/image/serverpage/image-id/8926i... recent SOTUs should be comprehensible to high school freshmen.
(full discussion at https://community.jmp.com/t5/JMPer-Cable/Regression-to-model... ; through 2018 — anyone have 2022?)
EDIT: keep in mind that the expected "general" audience for the SOTU has also expanded dramatically due to technological change in between 1790 and 2018...