The US is probably the worst launch market. The FDA regulates hearing aids so any new product would have to go through the FDA validation process, which is expensive.

Edit: I may have misread your comment, my apologies! I'm only loosely familiar with the US regulation on this matter and completely unfamiliar with other countries' regulations but I'd find it hard to believe there's any country more expensive to launch in for a medical device than the US, so for the OP I'd agree with you that the US should probably be a later market to target.