Neither was a dissappointment to me. However, they could have sold better if they had better third party libraries and weren't so slow to lower prices of games.
N64 cartridges made it costly to develop and manufacture. They made the limits on storage almost impossible to do what developers wanted to do. It also mean that $19.99 greatest hits series was out of the question.
GCN, Nintendo was too focused on profit per game sold, too kiddie oriented in design, and lacked third party support. If they had lowered the price of several first party games, parents during the holidays would have been willing to buy, because "hey look at all the $20 games". Smash and Double Dash were still $29 when I last checked. The thing was a purple lunch box. At 25 I don't really care what my game console looks like, but when I was 9 I wanted it to look cool and futuristic (i.e. Bad Ass). It lacked third party support because Nintendo didn't aggressively market the GCN early on and had a moderate initial install base, the discs had small capacity, and nintendo's demands were very high for acceptable game performance.
I would cite regulation, but I know you will simply ignore it.
