That doesn't really follow. We manage to understand people speaking English in their own accents well enough, so if people were to just write a phonetic transcr

That doesn't really follow. We manage to understand people speaking English in their own accents well enough, so if people were to just write a phonetic transcript of what they spoke, we should be able to understand that as well. A standardized spelling system probably does make the language a bit easier to read overall, but it isn't a necessity.