It seems to be like a weird artifact of academia not keeping up with technology. Academic publishing used to be a primary means of distributing research findings. At some point it became easier to distribute findings without an academic journal than with, as they generally use pay walls, can take a long time, and do not make the information available to everyone.
The workaround so far are things like sci hub or pre-print containing the same ideas as the final version but called something else to get around journal legal depts. Academic journals still have a function of recruiting peer researchers to review to improve the confidence in the research, but that could be replaced by a much more efficient & publicly transparent system using modern technology.