What is a Nintendo64DD?
This was the Nintendo's first system to use disks, well besides the playstation (which never got released). This system is not known by many and actually it's not a system at all! It's an extension! There were also not very many games. This system was only released in Japan which is why you may not know about this console.
If you heard of the Nintendo64DD before looking at this reply to my tweet on twitter @Pr0Julian
Did the Gamecube fail?
Yes, Indeed it did, mostly due to marketing, but also due to lack of games, yes Gamecube had good games like Double Dash or Wind Waker but then what do you do? There was Mario Sunshine but even that couldn't get Gamecube to be great, sadly the Gamecube failed pretty badly especially since it was also very underpowered compared to the XBOX and PS2.