But playing the role of the devil's advocate here one might argue that the major benefit of autopilots is that the data will be accumulated to the set of happened accidents, so that they don't happen again in future.

When comparing accidents of manual vs automated driving, manual cases don't have any learning effect (let alone communication of it and availability of that to other human drivers). Automated driving on the other hand has the theoretical benefit, if it's openly shared, that all edge cases of untrained accidents go asymptotically to zero over time.

But in order to achieve that there must be a law that enforces the use of the same dataset, and that defines this dataset as public domain so that all autopilots can learn from that knowledge.

This was actually my initial hope for OpenAI. And oh boi have I been disappointed there. Nothing changed when it comes to reproducability of training or availability of datasets, and most research of OpenAI seems to be spent on proprietary concepts.