What is wrong..... I'd rather put it, what was wrong.
The popularity of the .470 NE, or the tale about it. Not very many had them 40 years ago, but we all read Rurark - and so Winchester did the strangest thing. They made a cartridge to duplicate the .470NE - with a .458 bullet, since that was Americas pet from the .45/70 and other obsolete rounds.
And even went up 10 grains to make up for lower velocity, to 510 grs, in stead of the .470NE's original 500 grains.
In sted of duplicating the .450 NE with its 480 grains bullet, which was well prooved and higly praised. That would have given the desireable 2150 f/s a lot easier.