Of all the big retailers like Costco, Sam's Club or Walmart,    Target is absent from the hearing aid market.  They do not sell hearing aids online or in their retail stores.  They have either examined the market and determined that its not profitable for them - or its not even on their radar.
Who knows...we do know that things are changing at Target. The company has a new CEO, hasn't been meeting its sales forecasts in Canada and in the US the bulk of its sales are coming from discounted merchandise.
That means, the company's demographic is changing. Customers are focusing on sale merchandise or not buying at all. Either Target will have to re-establish itself as a higher quality, style-forward alternative to Wal-Mart, introduce convenient ways to deliver products to its customers like Amazon, or it will need to reorient its sales plan to compete against even lower priced stores, like Family Dollar  or Dollar General - I think Sears tried that and failed.
They may be looking for new ideas, new sources of revenue.  If a good percentage of their demographics are aimed at babyboomers,  it would not take much to open a hearing aid store inside Target - just duplicate what Costco does.
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