When I was in Radio Astronomy, publishing in APJ meant something, but when someone would publish an article pertaining to Radio Astro in Nature or some other publication, it was often looked down on as having less merit since it wasn't in APJ.
Personally, I know of a lecturer in my undergrad university who published in a more well known journal because when they suggested publishing in a less well known journal that was more niche and in-line with the field of their research, the chair of the department leaned on them and "strongly advised" that publishing lesser journal could lead to loss of funding for their research group.
Getting a paper in Nature will help you get tenure or win you that grant you need. Publishing in a no name journal is barely better than not publishing at all.
Because these journals are so prestigious, they can charge a lot for access. Every top school will buy access because it would be embarrassing if they didn't.
There is nothing stopping researchers from publishing in their favorite open access journal. In fact, they'd probably have a better chance of getting it published. However, they don't want to - those journals aren't prestigious enough. And without enough prestigious papers, they'll never make tenure.
Researchers who publish in these journals can publish anywhere, but they choose to publish in these for-profit journals.
Do you know why?