I've seen some very limited discussion about new modes of analog processing. For example, you can generatively produce an FPGA bitstream with a genetic algorith

I've seen some very limited discussion about new modes of analog processing. For example, you can generatively produce an FPGA bitstream with a genetic algorithm that does strange things. E.g. totally disconnected logic components evolving such that they influence the operation of each other via RF leakage within the die. There are no doubt other methods. Constructions which model neurons are also a possibility, as are other things. A lot of the analog in those devices is very high speed and must be put on, say, sapphire substrate or invokes some other complicated method, requiring wafer level integration or another package. The energy budget may be worse for digital at our current tech level but other effects like package size and package/wafer/process cost dominate. Spintronics, phononics, photonics, ... could also lead to new computing and reduced sizes.