> People don't grasp how easy it is to build data models like this even without privileged first-party data access.

People on this site probably understand this better than 99% of the world.

The problem is "What can I, as an individual, do about it?"

block ads, stay off most social media, don't use mobile devices while traveling

> don't use mobile devices while traveling

Some airlines don't even allow you to check in without using their app, unless you are willing to pay for a fee.

You can also exploit it for personal profit. As for stopping it, good luck. Best case is probably to degrade or poison data sources in a preferably legal way.