They do, and it's also mentioned in the article. While I agree, for many people the browser is effectively their os, and so we shouldn't discount the weight of browser notifications simply because they're not originating from the host os.
What's your point, exactly? Let's say we accept your premise that this is an unfair double-standard that Microsoft shouldn't have to respect... have you considered the logical conclusion that this creates? That the public should just... blithely accept Google-style nag prompts baked into literally any piece of software or hardware, even when they hold a paid license? I don't think a reasonable person would intentionally advocate for such a thing, so please help me understand what you really meant.
That's neither my premise nor the logical conclusion of the premise you invented.
A reasonable person should interpret my comment to mean that Google does the same thing, and if you feel a certain way about Microsoft for doing this, you should feel the same way about Google.