I would disagree and say rather that rocketry is finally maturing. Full flow staged combustion engines like the Raptor (which continues to push the envelope to INSANE chamber pressures) l, fully reusable boosters, super chilled densified liquid propellants, and the steep decreases in price per kilogram to orbit show an industry that is finally moving from its infancy into a mature and increasingly comoditized business model.
True there are no cutting edge new propellants on the horizon for traditional chemical rockets; but the efficiency and performance improvements still to be realized on these “old” technologies are mind boggling.
You might have well have said that the automobile/internal combustion engine was at a dead end with the Ford Model T. The basic principles involved are still in use in all ICE cars today; but the development of those principles is nothing short of amazing.