Doesn't open data make data monopolies more powerful?

"We live in a world where a few, mostly US-based companies hold huge amounts of data about us and about the world. Google and Facebook, and to a lesser extent Amazon and Apple, (GAFA) make money by providing services, including advertising services, that make excellent use of this data. They are big, rich, and powerful in both obvious and subtle ways. This makes people uncomfortable, and working out what to do about them and their impact on our society and economy has become one of the big questions of our age...."