while I agree with most of your points your example is exactly why we have them. I couldn't find the message you were trying to substantiate without reading your comments.
Technically low-level messages aren't important and usually a response to a user's purposeful action. They (low-level messages) also tend to include an aria call for accessibility purposes, something much harder to do in a registered page state.
Good points but more discussions are needed on a better replacement.
Finally! Your point about the GDoc feature is actually good. Depending on context, there's an opening for a new kind of component that informs the user constantly without the pitfalls of the snackbar.
I thought this was going to be about snacking at work, and how to be healthier... I was wrong.