Wouldn't that be expensive? I mean an optical disc is extremely cheap to make compared to a cartridge. I love the idea of going back to using cartridges, but I just can't see it being economically efficient for Nintendo. This was the main reason why N64 games were so much more expensive than PS1 games.
N64 cartridges were making up roughly 30% of the cost of the game ($10-20 depending on the size of the game and size of the cart). It's why Nintendo selects of the era only went down to $30 versus PS1's $15-20.
For comparison, a 32GB class 10 SD card is $7-10 dollars at retail, which would be noticably less for a wholesale purchase like Nintendo would make. Still pricier than a dual-layer blu-ray disc, but if you're expecting a good portion of your game sales to be digital going forward, it's less of a concern (you end up offsetting the price of the carts onto the consumers).