For example, I have been using Google or Apple for 7 years, and seeing that I was fingerprinted, tracked through third-party cookies, etc. I want to switch to a more private option.
But is it worth it? They know about me, they have now AI that can just use the behavior pattern for the last 7 years and still track me.
Again the question comes, should I become “privacy-focused” despite my data before I was “privacy-focused” used and sold?
You absolutely should. With time, the data they have on you will grow outdated, meaning they won’t be able to track an analyze your behaviour because they’ll have no idea how you behave now. It’s like the trail going cold. Hell, just becoming privacy focused already makes it near-impassible to be tracked, and since privacy-aware software doesn’t track, collect, sell or buy your data, what little they have will be much less useful. Also, if you live in the EU, the GDPR gives you a right to request the deletion of all data they have on you, and they must comply. Most other places probably also have laws in place to request the deletion of your data.