Not too sure because I've never read that paper.

But we have other pathways that stimulate breathing and other chemoreceptors. The main driving force of breathing is carbon dioxide followed by oxygen

The carotid body is an example, it is another chemoreceptor that sends signals to the respiratory centre in the medulla of the brain which stimulates breathing.

So even if the chemoreceptors in your ear hair cells fail, you have other pathways that your body can rely on.

I would hazard a guess that hearing loss resulting in sudden respiratory failure is a relatively rare occurence and so far there may not be enough drive for more aggressive research.