Interestingly it's still possible to do this. I'd cite the Behringer D, which has managed to get surprisingly close to the Minimoog; I've owned and disassembled a Behringer D.
At least with the one I had, it was designed in such a way that it continued to use the primitive electronic parts found in a real Minimoog, and key components such as rotary switches were designed to be similar to what the original device would have. The modern assumption is that all these things can be redesigned to handle barely the energy required by the waveform being passed: microminiaturized SMD components you'd get in cellphones, on microscopic traces. Behringer used some of the SMD components, but sourced others to be more like what you'd get in the old gear: wildly, wildly overspecced, so the waveform wold go through a switch that could pass two or three amps of current.
I've also seen a guitar compressor (from a different company, but you know Behringer is just as capable of making one this way, or taking their earlier designs and optimizing for cost once it's established), which was clearly designed like a cellphone. It was a flyspeck of a circuit, rather beautiful to look at in its tininess and elegance: I tried to play bass guitar through it and had to get rid of it as it sounded simply awful, taking away all of the instrument's tone. Not all of this was due to coupling capacitors designed to be as small as possible, though some of it was. Some of it was the sheer miniaturization of all components. This is never found in the 'vintage gear' or the modern stuff that matches it.
You can never design audio gear around only the bare limits of what is 'meant to be there'. It's a trap, there's a lot of success to be had in excess capacity to carry tone and sound. Interestingly, it's still really cheap and easy to go the 'vintage design' way, even if you're also using microcontrollers and SMD and all…