Before the internet, publishers actually printed journals on actual paper. This cost a lot of money, and it makes sense that universities payed for subscriptions to physical journals.

Today, the cost of these subscriptions hasn't changed much. But the added value is much less since everyone reads papers online.

They bought up a bunch of academic journals. Added value is arguably negligible now, but some of the publications have the highest profile in their fields for years.

If you're really interested, The Guardian recently did a very good longread on it: https://www.theguardian.com/education/2017/jul/10/the-lucrat...

Added value: Reputation. You get your paper published in an Elsevier journal, your reputation amongst you peers rises. Usually this means more funding and better career prospects.

Think similar to Fitch and Moody's in the financial sector (right?).

1) Largely through mergers and acquisitions

2) Network effect (although with newer technology (social media, cheap hosting, cheaper devops, etc) this value is dropping precipitously)