The enormous flaw in that argument is that words are meant to communicate specific meanings. While a word may convey many concepts, as you say, the meanings will be different for others who maintain a different "concept" of the word. That leads to linguistic chaos. While language and word meanings do change over time, the essential factor is that a majority must agree on meanings or language becomes useless as a means of communicating ideas.
I cannot agree with you. Which of the 430 meanings of the word “set” listed in the Second Edition of the Oxford English Dictionary is the “correct” one?