How is that fair? Note that this isn't a technical choice (you can preserve the previous defaults, that's just a well-hidden non-default option during the upgrade process) - it's using your monopoly position to make life hard on other software manufacturers.

How reasonable would it be if a chrome install had a light-grey disabled-looking customize word hidden amongst a wall of text that if you didn't find and click it would replace windows with chrome os?

This sounds like a power-grab.