Authors where paid to do the research and publish their work that produced the paper (that is what the grant was for). PLoS an Open Access publisher pays editors, type sets the work, finds a reviewer and publishes the work for free access on the internet. Reviewers are the ones that generally do not get paid for their work.

Elsevier makes over $3 billion dollars with the closed publication model. They force institutions to pay for bundles of journals they do not want. The Institutions often do not supply access to the general public despite the papers being produced with public money (and despite many of the Institutions being funded by public money).

Paying the cost upfront from the grant increases the availability to the public.

I think the Elsevier model will eventually be deprecated, at the least for the open sector of society (aka taxpayers money). People demand that when they pay taxes, they should not have to pay again due to Elsevier and I think this is a reasonable demand. Many researchers also support this.

>PLoS [...]

At low costs of $2k~$3k per publication[0]. Elsevier closed-access journals will charge you $0 to publish your paper.

>Elsevier makes over $3 billion dollars with the closed publication model.

Elsevier is also[1] moving to APC for their journals because is better business.

>The Institutions often do not supply access to the general public despite the papers being produced with public money

Journals (usually) forbid you of sharing the published (supposedly edited) version of a paper. You're allowed to share the pre-published draft (see arXiv). Institutions could (and some indeed do) supply those drafts on their own.

>Paying the cost upfront from the grant increases the availability to the public.

At the expense of making research more expensive and hence more exclusive. It's money rather quality that matters now. Thus it isn't unsurprising that Frontiers & MDPI, two very known open-access proponent publishers, are also very known to publishing garbage. It's ironic that once was said that any journal asking you for money to publish your paper is predatory, yet nowadays somehow this is considered best practice.

[0]: https://plos.org/fees/ [1]: https://www.elsevier.com/open-access

Authors may NOT be paid at all for their work, or may even pay to do it.

I am a self-funded PhD student and no one paid me for the work that went into my open access paper. As it happens in this case the journal waived the publication fee, so no one paid anyone anything except I suppose the nominal pro-rata portion of my university fees that I paid.

It seems that perhaps neither are inherently 'good models'? What would an ideal alternative look like?