People know, Facebook and Google getting crap for all their tracking is evidence enough.
The reason people don't care is because digital freedom/privacy is largely irrelevant to most people's lives. You can't convince someone to care about something that doesn't affect their life, they're too busy for that.
I think the reason people don't care, is because they don't know. The average person either doesn't know or barely knows That anything deeper than what they see in the user interface is happening on their system.
We humans are very much an out of sight out of mind type of creature. If we can't see it, it's hard for us to imagine that it exists.