> Call me crazy, but I think most people care less about Nike knowing what their shoe size is
They don't care because they don't understand. "Most people" think their shoe size or what ad they see doesn't matter because they're right, those things don't matter. What matters is that all of the data being collected about them will be used against them at every opportunity so that other people can get more money and power at their expense.
The data they give up will be increasingly used in every aspect of their lives. Restaurants will use it to decide how long to leave them waiting on hold when they call for a reservation. Employers will decide to hire them or not based on their purchase history, their health, or their political views. Stores will decide how much to charge them vs their neighbors for the exact same products.
The data they've been handing over will be used by corporations to extract more money from them. It will be used by by politicians who want to manipulate them and to create maps that will limit the ability for their votes to make any difference. It will be used by activists looking for people they can target for doing things they don't like. It will be used by law enforcement who will use that data against someone anytime they think it might help them make an arrest, or win a case in court. It will be used by their health insurance company to raise their rates when fast food spending in their zip code goes up.
The data "Most people" gave up thinking it was about shoe size and ads will be leveraged against them in countless ways by people they've never had any direct interaction with at all. The data never goes away and it ends up in the hands of hackers and data brokers who sell it to others. "Most people" aren't allowed to know who is accessing their data, how accurate that data is, how (or if) it is being secured, or what the people who have their data will be using it for.
Well, although they'll never be allowed to know specifically what their data will be used for, in a general sense they can be pretty sure it will be used to manipulate them, to categorize (and often miscategorize) them and to assign them a position in one or more unregulated digital caste systems that will increasingly limit their options and cause them to spend more money.
They don't care about data privacy now, but as more of them figure out that what they've been giving up is going to impact the rest of their life in ways they couldn't imagine they're going to start caring more and more.