These are good points. I hadn't thought about the perspective that the central processor in a heterogeneous multicore system may spend a lot of its time orchestrating rather than computing—whether it's a GE 635 with its I/O controllers https://bitsavers.org/pdf/ge/GE-6xx/CPB-371A_GE-635_System_M..., an IBM 360 with its "channels" https://en.wikipedia.org/wiki/IBM_System/360_architecture#In..., or a SoC with DSP cores and DMA peripherals—but it's obviously true now that you say it. I've seen a number of SoCs like the S1 MP3 player and some DVD players where the "central processor" is something like a Z80 or 8051 core, many orders of magnitude less capable than the computational payload.

(One quibble: I think when you said "HeartBleed" you meant Meltdown and Spectre.)

I think there have always been significant workloads that mostly came down to routing data between peripherals, lightly processed if at all. Linux's first great success domains in the 90s were basically routing packets into PPP over banks of modems and running Apache to copy data between a disk and a network card. I don't think that's either novel or an especially actors-related thing.

To the extent that a computational workload doesn't have a major "scheduling" aspect, it might be a good candidate for taking it off the CPU and putting it into some kind of dedicated logic—either an ASIC or an FPGA. This was harder when the PDP-11 and 6502 were new, but now we're in the age of dark silicon, FPGAs, and trillion-transistor chips.