Your instinctive reaction matches with scientific consensus.

https://en.wikipedia.org/wiki/History_of_writing

> Each historical invention of writing emerged from systems of proto-writing that used ideographic and mnemonic symbols but were not capable of fully recording spoken language. True writing, where the content of linguistic utterances can be accurately reconstructed by later readers, is a later development. As proto-writing is not capable of fully reflecting the grammar and lexicon used in languages, it is often only capable of encoding broad or imprecise information.

https://en.wikipedia.org/wiki/Origin_of_speech

> vocal languages must have begun diversifying at least 100,000 years ago

> Each historical invention of writing emerged from systems of proto-writing that used ideographic and mnemonic symbols but were not capable of fully recording spoken language.

And, of course, today we are going backwards to icon proto-writing, with all the same shortcomings.