While this feature is lucrative, it could easily end up confusing the user if implemented the wrong way (per-folder view settings etc). Primary reason being users would set per folder view for a handful of folders with enthusiasm, and after a while forget which view setting was used for which folder, and this would ultimately lead to frustration, forcing users to fallback to the default view. There is a reason why this feature was removed from 'nautilus' in 2012, and I’m sure lot of thought would have gone while making the decision.
We don’t want to spend a lot of time developing / restoring this feature, only for it to look good on paper with not many users actually using it.
That being said, I do think it would be beneficial to try this idea to 'Downloads' folder alone, with a different UI abstraction. E.g. '[x] Use Smart Download View' as an option in 'Preferences' etc, which would display the 'Downloads' folder as shown in image in the original post above, which sounds reasonable. That would address the main issue raised here, while not letting users to shoot themselves in the foot with per-folder view settings.