Yeah, well replacing your whole laptop is an upgrade too. The mainboard is by far the most expensive component, so saying "you can just replace it" obviates the point of the frameowork.
I'm honestly baffled by this. That's not their claim at all, I don't see them claiming that evergreen software updates are "the point" anywhere. They talk about repairability and upgradeability. They never claimed the 11th (or 12th!) gen had or would ever have Thunderbolt 4. I don't see at all why you think that software updates are "the point" of Framework.
My concern isn't about Framework's claim, but about their behavior. It seems like they are abandoning the 11th gen mainboards, which were still being sold until just a few months ago. This points to a business strategy of planned obsolescence for mainboards. My concern is that this isn't so different, from a price or environmental perspective, from the more common strategy of making the whole laptop obsolete.
Their behaviour of... not being able to change the hardware that's currently in your laptop?
You're still generating a lot less trash than replacing the whole laptop, but I have a hard time imagining how you can get the level of consumer-upgradeability you seem to want in a laptop form factor. You have to compromise somewhere.