The only theme I see as constant regards Nintendo is that they tend to be conservative with RAM, both capacity and bandwidth.
I also see using chips that are efficient in terms of die size and power consumption. Gekko was only 43mm2 and Flipper estimated die size is even lower since it is an LSI and incorporates other processors on the same die.
However they are definitely highly conservative when it comes to cost of their hardware which from a business point of view is not a bad thing. From a geeks point of view it hurts.
I agree Nintendo does not indulge in RAM speed or quanity either. They are balancing the systems power and memory speeds for efficiency and cost rather than performance. No point in oodles of bandwidth if the GPU and CPU are unable to take advantage of it.