Those stress patterns already do exist in sentences. What do you think the difference is between a word that is pronounced without its citation form primary stress ("at most one primary stressed syllable") and a sentence that is pronounced with several more or less equally stressed syllables?

The difference between primary and secondary word stress disappears when the word is put into a sentence.

There are stress patterns in sentences that don't exist in lexical words, but they do exist in compound phrases, and there is no symmetrical situation of stress patterns in words that don't happen in sentences.