The symbol "7" or"$" does not give you any clue to pronunciation, does it bother you?
Most people learn a foreign language as a written one. It won't be so difficult if caracters were everywhere. Then again, why don't languages with simpler spelling gain any advantage over English? So, one can learn a caracter and a pronunciation written in pinyin. When we learnt English we learnt the spelling and the transcription of every word. I can say that instead Mandarin has almost no inflection.
Finally, no one said that foreigners will know Chinese well, they will do it in the same degree as they do English today.
About English pronunciation, do you any language which is not Germanic but sounds similar to English?