No. ACM has been on a slow path towards making everything Open Access for many years now - driven both by internal and external feedback. Given that the ACM Digital Library (individual and library subscriptions) has been subsidizing other ACM endeavors, that making stuff OA is not something you can take back later, and that the required article processing charges (APCs) cause other problems, they have been rather careful with the transition.
They plan to make the entire digital library freely accessible by January 1, 2026.
I'm interested in understanding how the ACM is handling the transition to Open Access, particularly given that they offer a lifetime add-on to their life membership option. How are they addressing potential pushback from individuals who have already paid a significant amount to access the Digital Library? Are they considering making a portion of the Digital Library exclusive to paid subscribers even after the transition to Open Access?
Note that LIPICs [1] publishes the conference ECOOP chaired by Jonathan Aldrich. It is a very interesting alternative to ACM for conference proceedings: it hosts some great conferences and it has lower APCs. It does not publish journals though.
arXiv is more than twenty years old at this point. I think the rising opposition to exploitative publishers has ratcheted up pressure on other institutions to switch to an open access model more than arXiv suddenly causing policy changes.
In 2019 there was a big dustup when people thought Trump was going to issue an executive order requiring all federally-funded research to be open access. ACM as an organization signed a letter with a bunch of publishers opposing this idea. It's own membership (myself included) objected pretty strongly... and the next year ACM announced plans to move to open access. So, just maybe, they're actually listening to their members.
They plan to make the entire digital library freely accessible by January 1, 2026.
Here's a short article about timeline and implications: https://medium.com/sigchi/about-acm-open-cd544408559c
EDIT: for anyone wondering why there need to be APCs at all, Jonathan Aldrich gives a glimpse into costs and benefits of 'traditional' publishers: https://medium.com/sigchi/what-benefits-do-traditional-publi...