I don't care if anyone has a Xiaomi, Oneplus, Samsung, etc. Each brand is using a modified version of Android, and they chose to be compatible with each other. But for example the "blue vs green bubble" drama is a thing specifically because of Apple locking their unsuspecting users into a closed ecosystem. And it sure isn't Android's fault for not being compatible with it.
The more power a company like this gains, the worse will it be for the whole industry.
No, you didn't, or at least not at this level.
Sure, TV ads and even some old games had ads which were targeted to specific demographics (their audience), but modern digital ads are targeted to vulnerabilities of specific individuals (using location, search, purchase history, etc.). They're also shown much more often and baked into products which are specifically designed to target your subconscious psychology (using nudging, gamification, etc.) so you use them more.
The kind of data required for the level of ad targeting done now did not exist more than maybe 15-20 years ago.