I mean, the accountability lies with the company. To take your example, Boeing has paid billions of dollars in settlements and court ordered payments to recompense victims, airlines, and to cover criminal penalties from their negligence in designing the 737 Max.

This isn't really that different from malpractice insurance in a major hospital system. Doctors only pay for personal malpractice insurance if they run a private practice and doctors generally can't be pursued directly for damages. I would expect the situation with medical robots would be directly analogous to your 737 Max example actually, with the hospitals acting as the airlines and the robot software development company acting as Boeing. There might be an initial investigation of the operators (as there is in an plane crash) but if they were found to have operated the robot as expected, the robotics company would likely be held liable.

These kinds of financial liabilities aren't incapable of driving reform by the way. The introduction of workmen's compensation in the US resulted in drastic declines in workplace injuries by creating a simple financial liability company's owed workers (or their families if they died) any time a worker was involved in an accident. The number of injuries dropped by over 90%[1] in some industries.

If you structure liability correctly, you can create a very strong incentive for companies to improve the safety and quality of their products. I don't doubt we'll find a way to do that with autonomous robots, from medicine to taxi services.

[1] https://blog.rootsofprogress.org/history-of-factory-safety