I watched the segment with great interest, a thoughtful discussion by Adam and Alex as usual.
I tried it out on a couple of files from 2012, taken with my trusty old D2X. 12.2 megapixel files which up-rezzed to 40 something megapixels. They looked really good and I saw no real artefacts.
Alex discussed how this was a game changer, in that a lower resolution platform, such as a D300 could become relevant again. This is an exciting concept for sure, but it ignores the fact that resolution is not the only criterion for "progress" in camera design.
I currently own a D850, previously D2X, D3, D3X, D800, D810 etc and the march of progress has been undeniable. Not only with respect to resolution, but more importantly, autofocus, and dynamic range of the sensor. These attributes are not part of the Super Resolution algorithm, and are probably much more important that raw resolution. Low light performance and diffraction may be other matters though.
I think for photographers just starting out, this may represent a great way into the hobby; buying older gear and housing for a fraction of the price of 'bleeding edge' gear. It might also slow down the arms race to better and newer gear each time a new camera is introduced, if the main improvement is strictly resolution.
However, I feel that the D850 is currently at the top of the heap all round. It is hard to imagine much more improvement coming the way of DSLR technology. I am happy to stick with what I've got, and likely will NOT replace this camera in the future. It really seems to be a near perfect tool for the endeavour.
Mirrorless may be a completely different matter:)