WSJ report says flash media is getting more cost-competitive with discs.
A new Wall Street Journal report adds credence to previous rumors that Nintendo is planning to use cartridges rather than optical discs for its still-shadowy NX console.
The report, which cites unnamed "people familiar with the matter," suggests that advances in flash memory production have made cartridge media closer to cost-competitive with the standard optical discs. The report also suggests that cartridges "load faster, are harder to copy, and can be mass-produced faster than discs," statements that we'd rate as true, plausible, and confusing, respectively.

More importantly, though, using cartridges would be key for a system that can be used as both a TV-based console and a portable game system, as has been rumored numerous times in the past year. Housing an optical drive in a portable system adds significantly to its size and bulk, and the motor to spin the disc can be a significant power drain. Sony did manage to squeeze a proprietary disc drive into its PlayStation Portable, but it decided to shift back to flash-based cards for the PlayStation Vita.

The new report highlights just how little we actually know about Nintendo's future hardware plans just seven months before a publicly announced March 2017 release date. Nintendo has promised to reveal more by the end of the year, and some analysts suspect an unveiling may be coming before this month's Tokyo Game Show. For now, though, Nintendo seems to be sticking to previous statements that it's "worried about competitors" to justify the deafening official silence so far.
Though previous Nintendo consoles have been playable over a year before their launch, there's no law saying Nintendo has to stick to that pattern this time around. Still, with every day that passes without official word of the system, the chance of a delay (or a rushed launch) become greater.