Twist rates is a really big thing, the latest wiz bang round for LR comes in a rifle with a twist rate to suite VLD bullets, but the old time cases are stuck in the past.
To mention my hornet again, it's biggest draw back is a rather pathetic traditional 1:16 twist rate.
That stops me from shooting anything really over 45gn, I would have loved even a 1:14 or best of all a 1:10 twist.

I actually using trailboss worked up a subsonic load for it for use around camp, but it's very low volume and a faster twist would have let me use heavier bullets with a much more full case of powder.
As it is there's just a .4gn difference between subsonic rounds hitting the target and a cleaning rod pushing the bullet out the last couple inches of barrel.

But fortunately even at 1500fps and a much more full case of powder is still as quiet as a subsonic 22lr.

I think they could sell old cases in new rifles if the rifles gave an advantage over the old ones, things like take down, qd mounts, faster twist barrels, carbon fibre barrels and stocks ect.
They are better selling points then a new case that's essentially the same as a half dozen old ones.