I wouldn’t call it “myopic,” if anything it was forward-thinking...the cost of memory in the early 80s was high enough that including more than the 2 KB of built-in RAM might have made the Famicom/NES way too expensive. They designed the machine with internals that could be extended with extra memory and additional chips inside the cartridges, so that over the ~15-year lifespan of the NES as technology advanced and the cost of memory dropped, the cartridges enabled ever more powerful, impressive games, but stayed about the same price ($40 iirc) the whole time.