Actually, strictly speaking today's cellphone is not supercomputer class of 12 years ago, in fact not even really 20 years ago, but that's sane since optimizing for the measures of a supercomputer would have no relevance to anything a person does on a mobile device, and rarely even has relevance for a desktop. If we grossly oversimplify, a 20 year old supercomputer class system is about 10 times as powerful as a modern flagship phone.
But no amount of super fast memory technology will overcome that, and true that it's hard to imagine memory module width being the limiting facet of phone thinness (and besides, phones already are veering off into the 'uncomfortable for the human hand' territory, they really don't need more help on that, though there's always room for weight reduction).
On the power usage, any component trimming helps, but the screen is the biggest draw, then the radio, then the cpu/gpu, and ram is right behind that. It is certainly a power draw significantly higher than all but the aforementioned exceptions.
To further pile on:
Remember Samsung’s burning phones? That won’t be an issue with the LI-RAM because the light system could produce almost no heat.
A *RAM* technology is going to change Li-Ion chemistry to not be so volatile???
This is a pretty terrible article, which may be doing the original research a great disservice (hard to tell from the poor understanding and hyperbole).