I don't think there are any answers in new cartridges. They are not solving any problems, other than revenue generation.
If you really look at the real advancement in our industry, we have better bullets designed, and produced, to exceed anything available in the past. The faster twist barrels are done out of necessity to harness the new high BC bullets. Optics are so much better its astonishing.
The Hornady phenomenon of marketing is good at what they do, but their new offerings aren't really new, don't offer case capacities that are unavailable.
Consider the 6.5x55 or the 6.5 Redding to the 6.5 Needsmore.
How about the .22-250 Imp or the .22-243 Middlestead to the 22 Creedmoor.
Diane's 257 DGR to the 25 Creedmoor.
Still further, the 7 Mashburn or 280 AI to the 7mm PRC.
I could go on, but literally many older cartridges are capable if barreled for modern bullets.
The difference is the need to generate new revenue, rather than supporting existing inventory. The whole industrial world operates the same way. New equipment generates greater profits than parts support.