I really like the idea that I'm working on a tree (often a stack/list) of changes, and as the review progress I get this cross product of iterations over time like [a-better-way-interdiff-review-aka-git-range-diff](https://gist.github.com/thoughtpolice/9c45287550a56b2047c631...) showcases. In the end, the time dimension is useless after things get submitted, so the repository only gets the latest state of the change tree committed, which is simple and like the auto-squashed version you mention, but during review reviewers get to see the change tree evolve in an easy way.
That's something that the review tool can solve, and I agree that github doesn't handle it well. But other code review tools can show diffs between revisions independently of how the commits have been rebased or squashed over time.
I guess this might be a problem mostly on large projects on monorepos, where different systems that interact end in the same codebase, but there's a cost to be paid too if each system has their own repo, build/test/deploy infra and independent ownership.