“asked if Neuralink would perform another surgery to fix or replace the implant, but the company declined”

Evidence whether the company saw them as a person, or felt any ethical obligation…

with 85% of the promised functionality no longer functional

To be fair 85% of threads retracting doesn’t seem to translate to an equal amount of functional loss. The article mentions

Neuralink was quick to note that it was able to adjust the algorithm used for decoding those neuronal signals to compensate for the lost electrode data. The adjustments were effective enough to regain and then exceed performance on at least one metric—the bits-per-second (BPS) rate used to measure how quickly and accurately a patient with an implant can control a computer cursor.

I think it will be impossible for us to asses how much it actually impacts function in real world use case.

It seems clear that this is a case of learning by trial and error, which considering the stakes doesn’t seem like the right approach.

The question that this article doesn’t answer is, whether they have learned anything at all or if they are just proceeding to do the same thing again. And if they have learned something, is there something preventing it to be applied to the first patient.