These scientific journals hail from a time before the web was widespread and universally accessible.
In the present day, it is technologically feasible for every scientist to self-publish on their own blog (we'd probably want some new tooling for tracking and counting citations distributed across the web, but that's just details for some programmers to work out).
[QUESTION:]
Given the premise, I wonder the following. If we were to simply disband the existing publishers today, rather than trying to regulate them, what system would emerge to fill their place? Would it be similar to the existing system? Or would it be something more free-and-webby as described in the premise? Or something else entirely?