Do you feel offended by the sentiment? Or is it bannable or something?
Because I don't think it's a controversial statement. Nintendo franchises could absolutely flourish on competitor hardware. Moreso than on their own platforms, in my opinion.
It actually is a pretty controversial statement... Could is the operative word in your statement.
Let's take a quick look at how Nintendo is right this second:
On their OWN hardware, they are requiring outside help to meet their development needs.
On their OWN hardware, they are struggling to output enough content to fill a reasonable lineup and remain profitable, this is WITHOUT any major competition.
As of right now, the way they get the most out of their machines is that they control them. While there is certainly "nintendo magic", a lot of it is tied to their first party studios ability to know and work on their hardware and having direct access to the engineers that build said hardware. This is why Naughty Dog can produce visuals that seem so far ahead of other PS4 developers even though they all have access to the same hardware.
So yes, it is certainly controversial to assume that Nintendo will be more successful outside of their sphere of influence and control... Pokemon GO only highlights this, not detracts from it. Yes, it's definitely successful and will likely continue to be successful... but look at the cost of it. For what it is, Pokemon GO is a creative void. There is very little of the game series charm, no storyline, and the gameplay itself is super shallow.
That is the kind of experience we might get going forward for everything if Nintendo decides chasing profit is more important than standing on their own platform.