It's not that much of a stretch to imagine ultra dense wafers that can have compute, storage, and memory all in one SoC.
First, unify compute and memory. Then, later, unify those two with persistent storage so that we have something like RAM = VRAM = Storage.
I don't think this is around the corner, but certainly possible in about 12 years.
Pretty much every modern CPU is a hybrid design (either modified Harvard or von Neumann), and then there is SoC, as you have rightfully pointed out, which is usually modified Harvard, with heterogenuous computing, integrated SIMT (GPU), DSP's and various accelerators (e.g. NPU) all connected via high-speed interconnects. Apple has added unified memory, and there have rumours that with the advent M5 they are going to change how the memory chips are packaged (added to the SoC), which might (or might not) lay a path for the unification of RAM and storage in the future. It is going to be an interesting time.