OP - i'm pretty squarely on the side of modest cartridges, even for long range, compared to super overbore magnums. Lots of folks think they need to buy some hot rod cartridge if they are going to shoot a long ways. It seems like an effort to buy competency when they'd get a lot farther shooting something they can put a higher volume of rounds down range without torching a barrel, spending a fortune on ammo, and getting beat up with recoil. That way they'd actually understand why they miss or impact vs buying something with better numbers on paper.
One could take a look at all of the competitive long range shooting disciplines and what is dominating. It's modest, consistent, predictable cartridges. 6 BR variants dominating PRS, and some Benchrest/Fclass categories. 284 winchester variants dominating Fclass winners circles. 300 WSM being a go to for 1000 yard bench rest if the wind is going to blow.
All that said, aint nothing wrong with a RUM or 28 Nosler. They are fire breathers for sure and there's no disputing that they have impressive ballistics.
Punching factory nosler 180 accubond ammo into the ol calculator Here's what I get:
300wm @ 2950 FPS
575 yard drop - 10.7 MOA
600 yard drop - 11.4 MOA
Error if you range at 575 and animal is actually 600 = 0.7 MOA
300RUM @ 3250 FPS
575 yard drop - 8.4 MOA
600 yard drop - 9.0 MOA
Error if you range at 575 and animal is actually 600 = 0.6 MOA
So we're talking about 0.1 MOA increase in POA error if you have a 25 yard ranging error. Less than half of a scope click. It's Negligible.