Is there something I am missing? As I understand it the battle for privacy is long lost because most people, like me, just don't care. It's tremendous effort to fight against it. Even if you do manage to stay "off the grid" what's the upsite?
You or me might know to not easily give up personal information, and how it can specifically be used to annoy you (spam), or even be used maliciously (ID fraud).
But others may have less of a choice, having to pay with their data instead of money, or just simply don't have time to get educated. And they have to rely on the protective systems in place.
The battle for privacy is not lost. It's not one battle; it's a long-running social policy issue, and it's an arms-race. We get new laws such as GDPR and USA's COPPA and California's CPPA. We get new technical tools, or changes such as Apple killing the advertiser ID in their phones.
Lots of your past data has been collected. But you're creating new private data every day: your location, activities, etc. Try to protect that data better. And you can reach back and try to obfuscate old data that's out there, by overwhelming it with new data. Or make it irrelevant, by changing phone number, email address, physical living location, etc. The fight is not over, or hopeless.
What's the upside ? Well, shouldn't it be your right to control your public image and your data ? If you freely choose to expose all your data, fine. But it should be YOUR choice. The upside is more control over your life. Less exposure to thieves and scammers. Less risk for people who are unpopular minorities.