Because they're trustworthy. If you buy a package on Amazon or Craigslist, who do you trust to deliver it to your door tomorrow? People love the trope that their neighbor is trustworthy and the evil big company isn't, but in reality it's exactly the other way around. If you buy your heart medication you buy it from Bayer or an indie startup?
Big, long lived companies excel at delivering exactly what they say they are, and people vote with their wallet on this.
I don't know if Amazon or Microsoft are trustworthy or not.
But I agree with your point. And it gets very ugly when these big institutions suddenly lose trust. They almost always deserve it, but it can upend daily life.
And that is Amazon deliberately pawning counterfeits? Or is that other bad actors taking advantage of "Fulfilled by Amazon" infrastructure and its weakpoints?
Amazon has been ignoring the problem for a long time, and is well aware of it.
They're so aware of it that I'd personally (not a lawyer though) consider them culpable due to their inaction in making any substantial actions towards fixing the problems.
Big, long lived companies excel at delivering exactly what they say they are, and people vote with their wallet on this.