Well it's not about 100% privacy, because that's pretty much impossible, it's about MINIMIZING the amount of information they have about us, that information they can use in a variety of detrimental ways against us, to manipulate public opinion and keep us herded in and controlled, apart from money they make from selling it of course.

It's not a collective effort towards changing the general people or anything idealistic like that, since big tech is not gonna disappear no matter how big privacy-focused stuff gets (and it's certainly powerful enough to crush all alternative projects if they start growing too much, they'll never let themselves get overpowered), I view it rather as an individual measure to resist them ultimately thinking for me and guiding my life or my criteria or how I see myself and others.