As a reminder, it's the same people in tech we're trusting to build things like chat bots, "AI", cars that try to drive themselves and rockets that try to land themselves... etc.
You have to admit that if these same people can't be trusted to follow a simple "do not track" directive, humanity is in big trouble.
Sadly, we are. I didn't ever think of myself as an optimist until I realised just how pessimistic it is possible to become, as I've learned in the last 5 or so years. Now I realise I was quite an optimistic person, at least by comparison with my present self.
I mean, humanity is and always has been in big trouble. That's why history is full of disasters, mass death etc.
But I don't think it's that developers "can't" follow a DNT cookie. It's that they won't because it doesn't benefit their employer's financial interests.
Making a rocket that lands, on the other hand, does directly correspond to SpaceX's financial interests.