Commercial studios have racks full of boxes that start from $2000 each that fatten up and sweeten the sound, and a commercial track will patch every element through multiple boxes during mixing. The mixing desk itself will add its own sound.
Most of the boxes have analog circuitry inside them. Modelling it is not easy, and good models can use so many cycles it's no longer possible to listen to their output in real time (at least, not without using external hardware acceleration).
None of the mainstream music code environments - Overtone, SuperCollider, Csound, Max/MSP and so on - pay much attention to this. They mostly come with trivially simple DSP models which don't sound all that great.
Surprisingly, they also make it hard to use more complicated models even if you know what you're doing. Mostly you can't just add the model in user land - you have to add it as an external, and rebuild.
Commercial software from Korg, Yamaha, NI, UA, Access, and most pro and semi-pro VST makers puts more effort into sounding good, but the high quality models are somewhat proprietary and the code isn't often open sourced - although sometimes the models appear in papers from (e.g.) the ICMC.
