Elsevier had been buying academic journals for decades. A typical scheme is like Cell's story.
A professor establishes a journal under a big university's publishing arm. Then the professor thinks how to make money. Elsevier makes an offer and the professor accepts it. The journal becomes the property of Elsevier and the editors keep reviewing papers for free because it's good for their CVs.
Looking at older HN posts[1], Elsevier becomes another Comcast. That said, boycotts have not reversed the Group's profit trend.
[1] https://hn.algolia.com/?query=elsevier&sort=byPopularity&pre...