First of all I don't know why every system needs a 3 letter acronym. Just call it the NS, gamers will get it.
Second, I'm not being pessimistic when I see that in 3 years, the NS has sold 50 million. It's not unreasonable to think that in another 3 years, sales will slow, and Nintendo will release it's successor... So I think I'm being generous when I say it'll "only" sell another 50 million.