I'm convinced that at least 90% of "analog sound" can be simulated by taking the ideal block diagram and replacing every link with a parametric EQ->waveshaper->parametric EQ chain. Configuring those added components correctly is left as an exercise for the reader.
replyJim Lill's video on guitar amp tone is an interesting demonstration. Hear how close he gets to the original with an even simpler combination of EQ and distortion: