[a_wild_dandan]

These are all valid worries, but they all have the same fundamental solutions as current products.

> if we can't get IoT 100% right, or even 90% right, how can we trust IoT with physical interfaces into our bodies?

Trust is a risk-reward calculus for any product, whether it's BCI, the microcontrollers in your car, or the (hopefully uninfected) produce in your supermarket. Many folks will find the BCI value outweighs the risks for some feature set that matters to them.

> And then what happens if the company who made your implant goes out of business? What do you do when those updates stop?

Certain applications will have to be designed and evaluated with longevity or long-term support in mind. You don't need that when talking about cellphones. You do for today's pacemakers.