Lots of good points here. It can pretty easily summed up.
The N64 was cart based and a year late. Both the PS1 and the Saturn had a year jump on them, and both were CD based. Nintendo lost most "serious" outside support.
The Gamecube was goofy mini disc based, 2 years late to the DC, and 1 year late to the PS2, and then had to contend with the XBox. The developer support loss from the N64 generation continued.
After that, Nintendo stopped trying to be a big dog and decided to go after the elusive last remaining frontier, the "non-gamer". The Wii was vastly successful...but like most would expect, the "non-gamer" market quickly lost interest and returned to not gaming.
They've been tripping over their own shoe laces ever since, the WiiU is a commercial failure and I'm guessing the Switch will be more of the same. Starting with the collapse Nintendo/Sony joint venture of the early 90's, they have made one bad move after the next. If it wasn't for the GameBoy and their IPs lie Pokemon, they would have joined Sega in the grave.
On a personal note, I adore the GameCube, what a geat little system that thing could have been RE4 was beautiful.