Speed of memory isn't the most important thing. They would proberbly stick with slower speeds and go for a faster processor/graphics card instead. The amount of ram and horsepower you would nee to fully use it will not be in the next generation of consoles since they will not be faster then a 1080ti with i7/ryzen7 processor if they release in the next 2-3 years.
But would that be more on a set of 8GB chips (let's say 2 or 4) or set of 2GB to have higher bandwidth?
Doesn't matter, if you read the article these chips are being designed for the Volta GPU, high end stuff for quite some time and also expensive, higher bandwith is good but lets say the PS5 ships with 16GB or ram, realistic right, the difference between GDDR5 vs GDDR6 or HBM memory, which are both much faster would be a decision that costs milions.
Overall if you look at the 1080ti on pc, which uses GDDR5X and has 11GB's of memory right now its? 800? lets say the ps5 gpu is CLOSE to that, 2 years from now right prices are 1/4th of what they used to be, realisticly, they still need to build the rest of the console, they proberbly want to aim for 399 max 499 and they want to make a CPU that is much more powerfull, lets say Ryzen if they stick with AMD.
Overall the general rule of tumb has always been, more memory is better then faster memory (within limits) but espcially for an APU, which consoles use, where memory is shared between the CPU and GPU the amount will be very important, look at the PS4 pro which has the same amount of ram as the PS4, the difference with the Xbox One X is mostly in the amount of ram, cuz it just lets you do... more stuff.
So no, theres no reason to further analyse this, the PS5 and Xbox next will not use cutting edge technology used by graphics cards more powerfull and expensive then the consoles themselves.