We expect clean, readable code so we develop engineers who can write that code.
If we expect clean, readable commit histories (like any project on the lore. https://lore.kernel.org/), we can develop engineers who produce those commit histories.
There's an adoption cost but IMHO it's worth it.
I’ve tried to do this but the defaults on GH means even if I stack 5 commits each doing atomic things nobody reviews it as anything other than a single patch. And if I split them into distinct PRs the last one looks like the giant PR. And we’re in now I’m shepherding 5 PRs.
Until we have tools or at the very least processes that encourage that behavior nobody will do it.
And don’t get me started on commit message display.