That's a strong assertion that I don't find true. It is important and part
of the process, but if you breath correctly and don't have proper adduction
of the folds throughout the registers, or breath well and cannot get a proper
coupling of the vocal tract with the larynx you're screwed... no matter how
well you breathe.
No one's arguing with that....the person in question was asking about
exercises to help them hold a note or a long phrase.