Good point, but that's one problem that has, or had, little effect on my use of the 458 Win.
The reason being that I never used any of that early "problematic" factory ammo for any hunting of big game.
I put maybe 4 packets of later production factory ammo through my 458, mainly shooting pigs and chrongraphing.
Any serious hunting was done with handloads in my 458 just the same as with all the other rifles I use.
You see I don't use factory loads in ANY of my centerfire rifles.
For me reloading means being able to get the best from a rifle cartridge combination in terms of bullet selection, velocity, accuracy, economy, dependability, and of course safety.
With the reloaded 458 ammo and 500 gn SP and solid bullets I never experienced any of those dramas that the factory ammo was reported to produce back in the early days.
The guy who now has my rifle still has and uses some reloads that I put together 8-10 years ago some of which has been bounced around the Northern Territory, Cape York, Outback Queensland and New south Wales during that time.
Temperatures in some outback areas reach mid to high 40's (C) and despite all this they still work fine.
The 500 grainers were loaded to 2080fps for solid and 2120 for the softs.

Lots of things have changed since The 1950's.

I mean you could probably duplicate the way the 458 cartridge was first loaded and duplicate those alleged problems but you would be crazy to do so when there is a better way!
Modern powders and primers are capable of improving faults that existed in the past.

The big Nitro Express cartridges USED TO BE LOADED with powder and primers that eroded barrel throats, often burnt chamber walls and breech faces, rusted the bores and were very capable of doing permanent damage to the rifles.
Do we still load them like that or have we improved them by using more modern components?

So who cares if Winchester original factory loads didn't work in the early days.
Then was then and now is now.
It's all about keeping an open mind I believe.