It's pure rent-seeking behaviour of entrenched organisations. They outsource a lot of their stuff to India, and ask for a 3500$ fee in return to host it open-a

It's pure rent-seeking behaviour of entrenched organisations. They outsource a lot of their stuff to India, and ask for a 3500$ fee in return to host it open-access, or ask everyone who wants to see it 50-90$ but then they'll publish it for 'free'. Reviewers are unpaid academics, authors are unpaid academics, editors are badly paid Indians. The only ones profiting from this are the people owning the publishers. Look up some publishers parking lots on google street view. Springer for example has a Porsche sitting right in front of the building.