Thanks for the post. Very good read.
When coming to work from university (1989-90), I made a somewhat similar though more primitive design for the embedded software of a redundancy controller of a satellite modem. The various tasks (control of RF and baseband electronics, display and buttons UI, network management interface, etc) would run according to a scheduler, each in turn. No dynamic memory allocation, internal communication via global variables that are written only in one place. There was no mechanism to actually enforce this, it was just the principle in code, and the enforcement was possible because it was a one-man software project so I had no one else to blame.
This was written in PL/M (which looks like Pascal but is more similar to a primitive variant of C) on a 8031 microcontroller, from scratch (no 3rd party SW components at all - that was a long ago).
Later on, I used the same platform for a design we did on a telephone/data cable modem we designed for domestic use (We saw a need for internet enabled cable modem in 1992 and started work on a thing that provided POTS and 128 kbit/s over SLIP). That was also running a 8031, but as we wanted to make it dirt cheap, the board did not have dual-port RAM. The hardware wizards made it run with a hack on the regular RAM access so that the SW could only access RAM if it read any memory location twice: first read would just place the address bits on the bus, and doing another read would actually fetch the content. This enabled us to save several dollars per device.
(This was possible because the 8031 has an architecture which is not strictly von Neumann design: the code and address spaces are different memory spaces and you use different CPU instructions to access the different memories, so your program memory on EPROM works normally but your data memory in external RAM does not. There's also a small internal RAM in yet another overlapping address space which was not impacted by address bus weirdness.)
This is just to show what kind of strange limitations you sometimes have on the hardware in embedded devices. Unlimited virtual memory, large non-volatile storage instead of a puny i2C bus EEPROM... you just dreamed of those. Modern controllers with 4G flash are really huge compared to that, but they are still far below what people have on desktop computers, or even an Android phone.
The limitations in embedded devices indeed come from cost per device as well as heat, vibration, radiation, humidity and similar environmental factors.