You seem to be discussing a very different level of hardware development than the linked article is.
SoC design, along with FPGAs, and generally any digital logic oriented device lends itself well to software style development approaches because a large portion of it is software. The design of such devices is done in a HDL (Hardware Definition Language), not with schematics.
There really isn't a HDL for board level design (unless you count Spice I guess), mostly because board level design doesn't have the neat and clean abstractions that on chip digital design has. e.g. you can black box a 4-bit adder and glue a few together without much care about the implementation. You can't do the same thing with an audio pre-amp circuit that will be part of some mixed signal board as the implementation will often be driven by complex interaction with the rest of the design, right down to physical placement and layout of the circuit on the PCB.
Sure, I'm not saying they're equivalent. I'm just saying that this points the way.
There was also a time when making software was too expensive to make for modern methods to work. When my dad got started, machine time was way too expensive to spend it on things like frequent compiling and automated testing; it was cheaper to have humans stare very hard at paper printouts and simulate operations using paper and pencil.
That changed with the rise of the personal computer, and changed further as computing power got cheaper. Now developers can spin up whole virtual clusters of machines to test things out, easing the development of open-source software for those environments. If software is eating the easy end of hardware, that at least means that some open-source hardware will become plausible. But I hope the progress will continue over coming decades.
SoC design, along with FPGAs, and generally any digital logic oriented device lends itself well to software style development approaches because a large portion of it is software. The design of such devices is done in a HDL (Hardware Definition Language), not with schematics.
There really isn't a HDL for board level design (unless you count Spice I guess), mostly because board level design doesn't have the neat and clean abstractions that on chip digital design has. e.g. you can black box a 4-bit adder and glue a few together without much care about the implementation. You can't do the same thing with an audio pre-amp circuit that will be part of some mixed signal board as the implementation will often be driven by complex interaction with the rest of the design, right down to physical placement and layout of the circuit on the PCB.