So far, we don't have any indication that Tesla will continue the same "closed-source" policies with their mass-market models. In fact they probably won't. They don't sell through dealers, so their repair "bandwidth" is obviously limited. They have got to be planning to allow third-party repairs at some point.
I did not downvote you, because your point is reasonable. I do disagree with it because it assumes that Tesla is putting their customers interests first. Their history points to the contrary. Your first sentence outlines the main point. It's similar to assuming that any successful closed source software will be open source when the product end of life is reached. Imagine assuming Microsoft open sourcing windows xp when it reach end of life. What kind of incentive would Microsoft have to let continue to run an open sourced maintained version of windows xp? None. Their interest is in selling more new windows keys. Thats why I assume tesla will continue to not provide any sort of documentation. The incentive to do so does not exist. Now, regulation that forces them to do so would provide the incentive. Thats why the right to repair act is so important.