Looks like Microsoft’s slow play ad strategy is still in play. They’ve been talking about this for 5+ years so I’m not surprised with this.
The biggest mistake here on Microsoft’s behalf is that no one is made aware of these ads until they happen to stumble on them. No one is going to expect ads to be loaded in their paid-for OS, so a notification of that at first boot would be appreciated. Further, no one is given the option to disable them (though I’m sure it’d take little more than an editing of the hosts file). Finally, there’s also the fact that these ads haven’t decreased the price of the OS, else that’d be a point Microsoft would no doubt flaunt.