Sure those things were happening simultaneously but most of those folks spent all their lives organizing with real people who had much more similar class interests to them, and the media dissemination was a part of it. The largest periods of writing and publishing were often in exile from state repression. It was through their actual organizing and life experience that they had the position to be writing and debating such things. A bunch of westerners who have barely struggled for anything in their life, who benefit immensely from systems of oppression and don't have the same class interests as the majority of workers in the world, and self identify as communists but still choose to spend more time online than trying to organize in the real world, are not the people who will be forming a vanguard which also might not ever actually be formed. There is no promise that a vanguard must develop in any nation, especially the imperial core.

My point is mostly to highlight the reasons why I don't think you can create such an online space that will be very active, because the majority of people online who self identify as communists have no reasons for a space like this, they are looking to socialize and shitpost with a certain aesthetic. The .0001% of westerners who would want such a space without the casual elements would be such a small community of people that there probably wouldn't be enough going on in such a space to make it active enough and couching such a thing in a place like lemmygrad or hexbear seems like a better move than trying to remove the casual elements and have a purely studious, serious organizing space online.