And yes, you can build your own plugins. You cannot replace the thousands upon thousands of VSTs out there. You aren't replacing, for example, RealStrat, which is a supersampled virtual instrument, without re-recording the entire thing (do you know how? Is anyone going to bother doing it when they can use existing, conventional software?) and simultaneously reverse-engineering the algorithms used internal to it. You aren't replacing even something comparatively simple like an Amplitube without heavy-hitting, lots-of-money algorithmic research in the first place. (And, on top of that, I sure wouldn't want to deal with the patent encumbrances!)

And pardon my skepticism, but emulating latency-sensitive, CPU-intensive stuff like audio processing strikes me as a pretty foolish idea. When milliseconds count, your emulation layer just gets in the way. What benefit are you bringing to make additional failure cases and additional latency worth a user's time?

You aren't reinventing the entire audio world; as with many other fields, the lingua franca is C and not you and no matter how much you yell at the mountain the mountain's not gonna move. If you want to play, you have to play with (good metaphor for music in general, now that I think about it). Maybe you should rethink some of your decisions, or better constrain your ambitions. Because right now--and this may sound harsh but I'm saying it because I like seeing people succeed--it sounds like you're doing the software engineer That Guy thing and handwaving away difficult things because they aren't conducive to the postulates you're starting with.