The reason I think John Lucas' predictions might make more sense than that one is because Xbox 360 demand is, more or less, a known quantity.  It's much less than the PS2 was.  Whereas with the Wii, we have no clue how high the stratosphere is, we just know that retail employees in some places get hundreds of requests per day for a system that's already shipping at very, very high levels (higher than the 360 ever did, that's for sure).

It would need to have at least an 8 year long lifecycle ... but in the same ammount of time I dont think it will be able ...

I think it's likely for the main reason that Nintendo had to shorten the GBA's life to counter the release of the PSP. It's really not the DS' fault that it couldn't outsell the GBA in its first year in America. I totally blame that on the PSP.