How much did a 8GB SD card cost 4 years ago? If the 3DS came out in feb 2011 with 8GB carts, I can see a 2016 4DS with 64GB carts or at least 32GB with the option of 64GB+ in the future.

You're making stuff up now. You seriously think that a 64gb card is suddenly going to be less than $10 just because you can't write over it? It's going to be over half off just because you can't write over it? Even if that were true, it will still be exponentially more expensive for third parties to port their games on a cart, and that would not have garnered "positive reactions" from them.

No they wouldn't. The wording is always vague like that because SD card is a brand. A cartridge is not. If they were talking about carts, they would say carts. 

I have a box full of rare NES carts that I still play and love. The same for SNES, Genesis, N64... you name it. I'm never going to go all digital because when the servers die, or the company dies, so does my games.

I wouldn't mind that but most people still prefer buying physical games. And Nintendo's digital game prices are too high so that might be a problem.

Nintendo did say they wanted several form factors more than what they can already offer. This could also be a particular form factor that doesn't have an optical drive for those who want digital only, so they can purchase a form of NX that doesn't have an optical drive, which will in turn reduce the price of the console. They'll also be able to make it smaller, and can even run cooler, which will reduce the price even further.

$20 - 30% (retail cut) = $14 - 50% (profit margin) = $7 (posible current manufacturing costs of a 64 GB rewritable SD memory card).

Yes because Read Only anything costs less to produce than Re-Writable ones... Why on earth do you think Read only discs cost a lot less than Re-Writable discs as an example? Oh and you have not been in the meeting and neither has anyone except for third parties so you have no idea why the reactions were positive to begin with... For all we know, Nintendo didn't even show the full console to begin with but rather a dev kit

Actually that is incorrect... Here is the 3ds patent: "To this card slot 62, a memory card (SD card 64 in this embodiment) different from the memory card 58 can be inserted." Granted it also says "Cartridge" in the patent somewhere but saying that they have to be vague when it comes to SD card sounds like nonsense... Unless u have another patent where u are getting your info from?

http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=%2220100085693%22.PGNR.&OS=DN/20100085693&RS=DN/20100085693"

I was just talking about the image, not the written patent. I was mistaken.

Either way, memory cards, as in the SD card, are clearly stated for what they are. Cartridges are clearly labeled for what they are. And no matter what the price difference is between readable and non readable, it will still cost exponencially more money for a third party to port the same game on the NX, and that's after the actual costs of porting, just because of cartridges.

It is possible for them to release External Disc Drive for backward compatibility.

About this new Gamepad, it seems that it could be powered sorely through single cable, if they are considering multiple gamepad, they might reduce the screen size to cut the cost of the controller.

But the cartridge might have the extra perk of working with both the console and the handheld. I'm not saying you are absolutely wrong, I just don't want a digital only console. But if it happens I'll bow before you and aknowledge your far superior psychic dick.