Some of your assumptions are correct, in that there has been a decline (or major delay) in marketing ultra power aids. But there always been a limited amount of power aids on the market over the last several decades. Oticon Xceed just came out with a new power aid and I believe more HA manufacturers will follow. Reason why - over the counter hearing aids coming in 2020.
The “profit mark up” in HA prices is HUGE but when we start seeing cheaper “over the counter” hearing aids flooding the market, prices will drop, thus profit margins will drop. Competition will bring down prices and reduce profit margins but probably not in “ultra power HA” category. And since there will still be somewhat of a gross profit margin in producing/selling ultra power aids", HA manufactures will probably ramp up “new” offerings next year.
Yea money talks and fools walk and though I hate to say it - I bet people who need hearing aids the most (those in the severe to profound) hearing category will end up paying the most out of pocket - for what ever ultra power aids are offered in 2020 and beyond. So much for Uncle Sam helping the group that needs HA’s the most.
Also over the counter hearing aids are only for customers with mild hearing loss (possible mid-range loss). But if you have a severe to profound loss you out of luck buying anything of substance or quality at your friendly Walmart or Rite AId. So due to pure greed and profit making - I believe in 2020 will we see more new power aids.