We'd need a real breakthrough in physics to have such a technology that works at a scale even remotely comparable to what a low end digital CPU can do today. The thing is, there's not even any real evidence (at least to my knowledge) that there are useful threads that researchers know to pull on that could yield such a technology. Emulating analog hardware with digital hardware in anticipation of some kind of breakthrough isn't going to have any material benefits in the short to medium term.