> economic failure to build cheaper purpose-built hardware for things like sending audio over a radio.

You're literally just wasting sand. We've perfected the process to the point where it's inexpensive to produce tiny and cheap chips that pack more power than a 386 computer. It makes little difference if it's 1,000 transistors or 1,000,000. It gets more complicated on the cutting edge, but this ain't it. These chips are probably 90 nm or 40 nm, a technology that's two decades old, and it's basically the off-ramp for older-generation chip fabs that can no longer crank out cutting-edge CPUs or GPUs.

Building specialized hardware for stuff like that costs a lot more than writing software that uses just the portions you need. It requires deeper expertise, testing is more expensive and slower, etc.