There will never be two or fewer consoles because there will always be an audience for cutting edge technology, and one for casuals. There has been a hardcore and a casual in every generation.
This one:
PS3/Wii
Last one:
Xbox/Gamecube
The one before that:
Jaguar/64
Before that:
Neogeo/ SNES
before that:
megadrive/NES
EDIT: i meant that there would always be at least 2