I'm really surprised at all the casual dismissiveness here. A full-screen ad on boot that must be manually dismissed and defaults you to the buy button is clearly intrusive, in a way that Sony and Nintendo haven't really replicated. There will be people who see the prompt and will waltz into a purchase, these tricks are employed because they do work even if in a small degree. Or did we forget about the years of kids racking up credit cards?
To be clear it's not a huge thing, it can be dismissed really quickly, but it's an escalation that deserves to be called out. Not to get all slippery-slope but it's very easy to imagine this getting more annoying - loading up every time you boot, multiple ads you have to click out of, a timer before you click out of it, etc. - and it deserves to be called out before it gets there.
(Also yeah the Forza and Starfield ones were also intrusive. They are very slightly mitigated by those games being on Game Pass and the default assumption that if you're using an Xbox you're gonna have a Game Pass subscription, though that's its own can of worms).