Hearing aids might fall into this category, but unlike the others on your list you need to deal with the FDA. The FDA should really be called the IPA - Incumbent Protection Agency.
Compact in-ear selective audio filtering. For example, block all noises except human voice.
Or a simple noise attenuation mode that can be controlled from a smartphone.
I took so many pointless medications over the years. When I was younger, I just figured if the drug/devise was FDA approved; it must be efficient? I was wrong!
There are also huge classes of drugs that are obviously effective and beneficial (pain killers/nsaids, antihistamines, blood pressure medications, antibiotics,).
If the FDA was less strict then drug companies would develop drugs that actually worked, but also had side effects (basically we would tip the balance back in favor of effectiveness over safety). While it would always be ideal to have a drug that worked perfectly without side effects, it is always better to have a drug that works than one that doesn’t. You can always choose to not take a drug because of the side effects, but if the drug is not sold then you don’t have a choice.
TI graphing calculators for high school students?
Lots of students already use Wolfram for graphing, the problem is use in proctored environments.
I can appreciate what the FDA does, but sometimes there comes a point where it is preferable to provide warning and education to consumers but let them choose which product they wish to use.
You would also want to never plan to travel to the USA ever again - the penalties for ignoring the FDA are not minor.
Which implies the FDA doesn't ban them. If the quality of $25 aids is not good that's another issue.
the Theranos story i think clearly shows one more time why such protection from "disruptors" is necessary. Unfortunately we still don't know how to do it more efficiently though.
My personal favorite here is FAA - who basically stalled to the complete halt the aircraft development for the last half of century, yet even here i understand the rationale behind it.