"Only 33.3% were concerned about their personal contact information like email address and phone number being shared with third parties, while 10.2% were worried about their friends and contacts being shared."
Can you find me one that says most did?
Because I can't.
Truthfully, if people cared half as much as hacker news thinks they do/should, it would already be a solved issue.
I can easily imagine people not caring about third parties knowing their phone number and email, thats already a lost battle. Everyone is used to giving those out.
Their search history though? their private chats with their friends? the websites they visit when they are alone? Their medical history?
The things they have bought themselves in the last 12 months? their favorite magazines?
Take some time and talk to people, I agree with the studies you found that said people dont care about their contact information, but ask people about other information.....search history is expected to be private, IME, by people who are not tech savvy. The same with their other private actions.
""93% of adults say that being in control of who can get information about them is important; 74% feel this is “very important,” while 19% say it is “somewhat important.” 90% say that controlling what information is collected about them is important—65% think it is “very important” and 25% say it is “somewhat important.”