That doesn't track (pun not intended). It's a binary state so either side has to be the default, they just changed which side the default fell on. Prior to the change no opinion expressed and expressed intent (in favour of tracking) still looked the same.

Microsoft made the default be, well, the default preference - what most users would set this setting to if they had to look. That's a good and sensible default.

The only reason why the advertisers were so unhappy about it is because what they do is neither good nor sensible by most people's standards.

I'm sorry but the word is "consent" not "intent" and that's literally how consent works.

If I (a complete stranger to you) walk up to you and kiss you on the lips, it doesn't make a difference whether you're wearing a t-shirt informing everyone you don't want strangers to kiss you on the lips or not - I don't have any basis on which I can presume to have obtained your consent so I'd still be violating your rights.

This is very much a "tech bros don't understand consent" case: if you do something without consent, you better have a damn good reason other than "but it's good for meeee" (or "good for my bottom line"). "My business model depends on it" also isn't a good justification - there are plenty of business models that depend on things that are unquestionably illegal, we just refer to them as "criminal enterprises" rather than "disruptive startups".