As someone who has run a bunch of publications solo, all I will say is this: Everything you said sounds great in theory. But it's not always possible in practice.
I know too many editors (myself included) who struggle to manage to do their own writing - whether on Medium or elsewhere - or see to their personal lives or families or self-care because of the relentless demands of Medium, and publications. We never get a day off if we're solo editors and it is bloody exhausting.
And there is no pay for it - only several hours a day spent seeing to the adding of new writers, the editing of current writers, chasing some of them down because they haven't checked for notes - or have acknowledged them but then not made the changes ... and those hours disappear and we never get them back.
Often without much by way of gratitude or even a little acknowledgement of appreciation from writers.
it's true, some publications leave us languishing for several days without so much as a note, and as a writer, that sucks for a bunch of reasons. It's also unreasonable not to at least leave a message to let writers know what's happening, unless there is some unusual circumstance. As a general state of things, though, it's not a good way to run a pub.
But what you're suggesting is simply not possible as a standard, particularly for small pubs or ones with only one editor. We have lives, too, and it's unfair and unreasonable to expect that we should be chained to our computers because writers can't wait a couple of days sometimes.
We put up with a lot that no one ever hears about, and although you assist as an editor, I don't know how long you've been doing it or how much you've seen, but when you are the pub owner and the responsibility is on your shoulders, it's much more difficult.
A perfect example of what we put up with is here in this piece by Vidya Sury:
https://medium.com/namaste-now/sharing-some-insights-as-a-medium-publisher-and-editor-3677c01f4428