When was this "fact" spoken by Nintendo?
Your analogy was wrong. The two situations are different saying anything other than that is delving into the hypothetical.
There's no point in speaking it out. Nintendo already had a partnership with Platinum when they were doing TW101, and considering Bayonetta 2's situation, it was a perfect opportunity to go the extra mile and get a hardcore IP on there that a lot of people love. Bayonetta is niche so save for public goodwill and hardcore recognition it's not guaranteed to be a system seller apart from hardcore people on GAF for example.
Similarly to Platinum, they're partnering up with Atlus. Out of that there's bound to be some additional goodwill from it.
Your last part can be said about any third party exclusive. Theres plenty of chance for MH to evolve on the Vita and let it reach new sights and an expanded base.
Monster Hunter is said to be under a Nintendo contract. Persona isn't. Is Atlus satisfied with their sales? Probably, but that doesn't mean a publisher should settle for less if they had the chance. That'd be stupid. P3 and P4 came out on the only reasonable console during their time. Persona 5 is coming out at a time where most consoles will mostly be completely unified in terms of just running it the way it was designed.
Opportunity cost. They could spend there money in better places that could benefit the WiiU more,
I could only agree to that if we really knew the innings of what it is Nintendo sees beneficial to their platform. Relations with Japan developers is one of those no doubt however, and since SMT is continuously doing well on Nintendo platforms to the point of Nintendo soliciting a crossover, Atlus' second major franchise would probably be seen to them as a good opportunity.
Are talking about future releases? Persona games take a long time to make and we usually only get one per generation. Whether theres a late port to the WiiU of P5 FES or P6 etc is anybodies guess and relies on how P5 did. Lets not get ahead of ourselves. I hope I understood that part you were saying correctly though.
I'm mostly talking about how whenever Persona 5 does come out, Wii U's install base will feasibly have grown enough to support the game doing largely similar numbers on it like the previous games did on their preceding platforms, because as I understand it and as others have been saying, Persona isn't that much of a super seller. Basically as everyone's expecting, "wait until the Marios and whatevers appear on Wii U and there will be a bigger audience for it".
I agree, there's a risk involved. But in terms of possibility I'd say there's a light sliver of a chance which perhaps we'll just have to agree to disagree on. It has no bearings on me wanting it on the platform necessarily. If I had the chance I would probably buy it on the Wii U as a way of supporting that kind of release and show that there's interest on the platform but I've been expecting and waiting for it to happen on the PS3 for some time, and a PS3 exclusive wouldn't be hurting me that's for sure.