This type of logic doesnt even work and if this does happen it would be very weird.
The Sony "10 year plan" doesnt mean 2gens it means they support the console for 10years look at the PS1 it was supported for 10 years by Sony and the PS2 is pushing 8years and good games are still coming out for it and will easily last the 10year plan same as the PS3 will.
End of 2014 Hardware Predictions (03/03/14)
PlayStation 4: 12-15million
Xbox One: 7-10 million
Wii U: 8-9 million (Changed 01/04/2014 from 7-9 --> 8-9 million)