Why Do I Care So Much About Privacy? - YouTube - watch that for some consequences that have happened due to giving all of your data to Big Tech.
Also, since Big Tech shares your data with everyone: your data could be used to influence your credit score, health insurance rates, car insurance, heck even your college admissions. Could be used to influence your background checks for jobs.
Look at the social credit system that China has. In China, the government obtains data using cameras. In the US, the government obtains people’s data through Big Tech and PRISM programs.