I think the name change had something to do with it being adopted by a company for commercial production. The wildcat round was called the Whisper.So how did it go from Whisper to Blackout? It would be cool if Whisper was for subsonic loads.
Why wouldn't the powers that be, who ever that might be, stop producing the 458 Win Mag and just use 458 LOTT?
Because there are still a lot of people that like the 458 Win Mag. On top of that, there are a lot of older rifles that are chambered in 458 Win Mag, so if they are going to keep producing ammo for it, they might as well make new rifles in it, too. This is true of a LOT of rifles cartridges. The 300 Win Mag is an example of that.
The 300 WSM is an inherently more accurate case design and can be loaded to about 98% of the capabilities of the 300 Win Mag. Now try to convince 300 Win Mag fans that they should replace their rifles with the 300 WSM. GLWTS LOL!