A gradual decrease will eventually happen, obviously. A cliff I don't think so, in Ninty history it happened only in two situations:
a) the product was a failure (Wii U and few others)
b) Ninty botched the gen transition and killed a successful product too early (Wii)
NS quite obviously can't be defined a failure, so the only possibility for a cliff is Ninty killing it like it did with Wii.







