It’s been a fairly populous space for some time, both in the laboratory and in commerce. Early commercial entries included Agenda, More, Frontier, and (of course) NLS/Augment.
I do think that Roam did a good job of publicizing itself. Notion did, too — did you see their venture funding?
The first wave of “knowledge management” tools had the bad fortune to be marketed into the teeth of the stagnation economy of the late 70s and early-to-mid 80s. In the U.S., the term became associated with efforts to deskill office work and to downsize staffing, and as a result the term became toxic for some time.