I am familiar with a couple of those. The 450 Bushmaster will not feed from a magazine with more than five rounds. The 458 SOCOM will as it was designed with enough taper to feed from magazines. And neither of these rounds are particularly impressive. How much better are they compared to a 44 Magnum from a lever action?, probably a similar rainbow trajectory making them short range things at best. What I have seen for the 300 BLK is a lesser round compared to a 30-30. .300 Blackout pushes a125 grain projectile at 2,220 FPS, I am doing that with a 170 grain bullet in a 30-30 lever action around 35 Kpsia. I am not familiar with the rest, maybe they are flash in the pans, so to say.
A good test of staying power will be in 20 years. If brass for any of those rounds is still being produced, then the round could be considered a success. In the decades I have been reading about the latest and greatest rounds, almost all of the hundreds, if not thousands, that have been introduced, and you can't find brass or ammunition. I just remembered the
307 Winchester, another end of history cartridge. Click on the link and see if you can order a box. I am confident brass for the 223 Rem will continue to be produced for the next 50 years, along with the 30-06 and 308 Win.
Unless I am mistaken, which my ex-wife used to indicate was more often than I was right, all of the chamberings I initially indicated were built specifically to fit the confines (obviously some would say limitations) of the AR platform.
What others see as limitations, I see as the platform's greatest strength. I am by no one's estimation a great gunsmith. But within a couple of years I was able to learn by trial and error almost all of the in and outs of how to assemble ARs (AR22, AR9, AR15, AR10/308, et al) to fit any caliber, need, want, whim or folly I chose.
And while they may not match others' ideals of what the most powerful cartridge in a particular caliber should be, they more than exceed my wants/desires in a relatively low cost, interchangeable, ever evolving and eternally tinkerable platform. .300 BLK may not meet your expectations of what a .30/30 does, but that's not what I was measuring it against to begin with. I can't build a 5 lb., silenced, subsonic, side charging .30/30 that my mother can use for home protection (probably more accomplished people than me can), but I can and have built one in .300 BLK. And in .350 Legend. Even in 7.62x39. And next month if I decide I no longer need it for that purpose but want to take it pig hunting, I can swap out the barrel, put on a thermal scope and handload some 110 grain or 170 grain blacktips and go do that. And if I think that might be a little underpowered I can put on one of my dozen .450 bushmaster uppers instead.
As far as staying power over the next 20 years, if I'm still alive I'm pretty sure I will have more than enough brass for all the different calibers my family currently handloads for, which is well over a dozen. If the market decides it no longer wants to support my pet calibers, I've got plenty of extra bolts, parts kits, buffer tubes/springs, barrels, receivers and so forth to last me 50 years and then probably another 50 on top of that.
I don't have anything against non-AR style rifles or other chamberings that don't work in an AR. I have quite a few of those. Thankfully I still live in a state, for now, that let's me have both. My opinion, respectfully.