How do you mean? I think the point of those ads was to convince people to rethink what a computer is and whether they needed a traditional one or whether they could do everything they need on an iPad. I don’t think that message contradicts Apple’s stance on keeping Mac/macOS and iPad/ipadOS separate.
I think where Apple contradicted themselves was in the keyboard. They criticized touch screen laptops and then essentially gave the iPad a laptop form factor with the keyboard. My view was that they had painted themselves into a corner and either needed to retract that statement or add some kind of cursor support. As it turns out, they chose to stick to their statement and add cursor support. Maybe internally that was the plan all along, who knows.
Everything can change, sure. We really don’t know what Apple will and won’t do. We can only give our opinions regarding likelihood based on what we observe (and whether we choose to take Apple at their word). I think iPad mouse support came about because of Apple’s aforementioned contradiction, and the relatively high return on investment, and because they figured out a good “iPad” way to implement it. I’m sure Apple could figure out a good way to implement extended desktop as well, but the difference is it would be much more work for Apple and developers, and I’m guessing the demand for the feature is lower. So it would overall be a much lower return on investment, therefore not as likely to happen, or happen soon. But they may do it at some point if they are really intent on pushing the iPad further into laptop replacement territory.
There are some things that I think are even less likely to change in any foreseeable future, like sandboxing and limited background processes because these seem to be pretty core to the identity of the iPad.