And Wiley / ProjectDEAL just yesterday reached a breakthrough: http://www.sciencemag.org/news/2019/01/groundbreaking-deal-m...

Suprisingly little coverage, but things aren't looking great for Elsevier.

Not quite: see this list of all such journals and events: http://oad.simmons.edu/oadwiki/Journal_declarations_of_indep...

The editors of Topology resigned over the high price (apparently it was $1558 in 2004: https://pages.uoregon.edu/dps/journals.php), and started Journal of Topology which at the time of announcement (https://www.lms.ac.uk/sites/lms.ac.uk/files/About_Us/news/20...) was said would be published by LMS (in partnership with OUP), and priced at $570. Looking at the page now, it is still published by LMS (in partnership with Wiley now), and I can't figure out the pricing. It is fully possible that the price has increased, but there has been no change from free to non-free. Back in 2006, "free" was not one of the conventional options for a journal. Now it is.

As for "a journal is not an easy task to manage", my favourite article is about the Journal of Machine Learning Research, the leading journal in the field of machine learning: https://blogs.harvard.edu/pamphlet/2012/03/06/an-efficient-j...

Often, journals aren't founded by the current publishers but instead by people who do actual research in that field. Then, a publisher approaches them and offers them a lot of money. Who would decline such an offer?

You are right, this move might just be a strategic measure to get more money from the publisher.

That's not exactly the story with Journal of Topology. It's published by the LMS, which partnered with Wiley.