That's not what "distributed system" means.

What's your definition of "distributed system" then?

Two flipflops interconnected on one wafer. Two flipflops inteconnected on one PCB. Two flipflops interconnected with a cable between two PCBs. These are all "distributed". They're all subject e.g. to the CAP theorem. Sure, the probability of one flipflop failing on the same wafer is quite small. The probability of one flipflop failing on one PCB is slightly larger. But fundamentally all these systems are the same. If you have two computers on a network you can make the probability of failure (e.g. of the network) pretty small.

I start counting them as independent computers when they have their own firmware.

It absolutely is.

distribution of signals within smaller systems (microcontrollers, ASICs, FPGAs, etc) are all distributed systems. Ask anyone doing any kind of circuit design about distributing clocks and clock skew, etc.

If you read the article, you’ll understand it’s about our computers being networks of smaller computers. The SSD, GPU, NIC, and BMC has its own CPU, memory, and operating system.