Yeah, I understand that. At some point in the post I mentioned that it would definitely be the greatest approach if we had a "Followers" category in the mailing tool provided by itch.io. I think this is the best option.
I understand that devlogs are how you designed this gamedev-followers communication, but it is a bit different. When we write a devlog we often want to get attention from those not following us yet, taking advantage of getting the devlog exposed in the devlogs page, so is likely that people who didn't follow the project sees a devlog and decide to follow it.
Some times we want to deliver a different message to those who are already following the project, knowing that they already follow us, we can direct the message towards a less "convincing" message and just talk about stuff that are not that appealing to broader audiences, as a devlog is more likely to reach.
So that's the take I would suggest: allow us to somehow mail our followers.