I know we all hate Elsevier, and I do, too. But the assumption in this threat that one could get rid of publishers without any thought and with absolutely no downside is simplifying it slightly too far.

Elsevier currently has a margin of about 35%. That's a lot, and probably too much. But it also means they are spending 65% of revenue on something. Even assuming a decent chunk is marketing and sales, there are a few billion in that industry being spent on editing and coordination tasks.

Going from a final draft to a published, peer-reviewed paper involves quite a few menial tasks, and scientists will either need to fill those roles themselves, or someone needs to pay someone else.

This is well proven by the current alternative, Open Access journals: they charge authors fees in the high 3-digit range to cover their costs.

So, for authors, Open Access means going from providing your work for free to actually paying to publish your work. Of course the institutions will usually cover those fees, and they have exceptions for people who can't afford it (payed by those who can).

The research will then be freely available, which is great. But the changeover isn't done with setting up some CMS on some virtual server somewhere.