I posit that the youngest among us will live long enough to experience a time in which Trump's waterfall will be considered every bit as historic and iconic as the NGLA windmill.
The reasons for its construction will long since have been forgotten by most people, but the fact that the damn thing has been there for 70 years -- and catches the eye, and is a signature feature of a much-talked-about course -- will be good enough to justify its existence.
But, as with the NGLA windmill, I doubt if many others will be built in imitation or tribute, because both are essentially pointless.