At an estimated $100k (or more) and "production runs numbering in the mere hundreds", I don't think the Infinitis will saturate anything.
But,yeah, I think Nissan would be better off keeping the GT-R exclusive.
But one can spend over $75k on a
Camaro Z/28 nowadays (I paid < $8k for a brand new Camaro Berlinetta back in 1979), so maybe $100k isn't a big obstacle any more.