How much did mario, zelda, and smash help the n64/gamecube? How do you define "significant impact"?
N64 released nearly
2 years after PSX and Saturn (which was quite succesful in Japan) around N64 launch popular 3rd party series like Resident Evil emerged and N64/Nintendo was basically completely on its own by then. Shortly after FF7 and two consecutive sequels with FF8 and FF9.
Similar situation with
Gamecube, late release ca.
1.5 years and right before Gamecube release PS2 got Final Fantasy X, again Nintendo was on its own.
After that there was PSP and
NDS released at the same timeframe. Winner NDS even with a very bad 3rd party support in its first 2 years.
Then PS3 and
Wii released at the same timeframe. Winner Wii, even with no significant 3rd party support and Nintendo pulling the plug in 2010 for their next-gen systems (3DS and WiiU).
3DS 10 month headstart. Winner 3DS.
WiiU released last December, with promising 3rd party collaborations on 1st party franchises and DQX+MHTri as a starting point for possible further releases.
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Fazit:
So far the only times Sony won was when they had a headstart for at least 1 year. When they didn´t they lost everytime against Nintendo so far.