They really aren’t though. Contrary to popular opinion, the .270 is not just a .30-06 necked down - it’s based off the slightly different .30-03. Try to make some .270 brass from 06 brass and let me know if it was worth the effort.
Let’s look at the technical side of this for a minute.
The .270 and .30-06 headspace on the shoulder. While the headspace dimensions are nominally similar, they are not the same. The shoulder is by no means the thickest part of the case. Given that the operating pressure of a .270 is usually around 65,000 PSI, wheras max on a .30-06 is around 60,000 (assuming a fairly modern load anyway, older stuff is usually loaded quite a bit lighter and the guns from “back in the day”, which we’ll consider to be the 60s, will often have trouble with this), there’s trouble on that front too.
If you have a right handed remington 700, look at the left side of the action, right around where the chamber is. See that hole? It’s there to allow pressure to escape if the case ruptures because you’ve done something exactly like what we’re talking about here. Without some allowance like that, the pressure either comes back at your face, or out through the barrel - which way it goes depends on how tough your action is.
Besides headspacing on the mouth (which isn’t the thickest part of the case either, but won’t result in big troubles in the case of a rupture as everything will likely go out the barrel - the bigger issues with semi-autos in terms of overpressure and case design is an improperly supported web, which will give trouble and generally vent into the magwell if the gun isn’t designed to allow it to go elsewhere), the operating pressure of 9mm is only 35,000 or so, and the .380 is obviously much lower at 21,000 or so, you can’t really apply the same logic that “because it works there, it will work here”. That’s safe because you can’t really hurt a gun designed for 38,500 psi putting 21,000 psi worth of pressure in it.
You certainly can harm a gun rated for 60,000 PSI (and this assumes a fairly modern gun, mind you) by putting something running at 65,000 PSI into it. Will it blow up? Probably not, though I can tell you anecdotally that it can. Will it result in wrecking your extractor and possibly jamming a case in the chamber in such a fashion that just banging it out doesn’t often work? Absolutely. Yet the game treats this as an everyday activity. It also bungles the real world performance of the .270, but that’s not as much of an issue as it is just a game.
The other cartridge that comes to mind as having the same issue is running the .45 Super through .45 ACPs. Even amongst modern guns, and despite the cartridge being built exactly for that, there’s more guns out there that will not stand up well to it than there are guns that will. Same deal, I can tell you tons of anecdotal stories of guns requiring repair after someone has done just that.