Synthesizer/synthesis purists will argue that you shouldn't try to emulate acoustic (and lets throw into that electromechanical) instruments with synthesizers. But such purists aren't keeping the profits coming for the manufacturers of electronic keyboards (synths don't have to have keyboards or be controlled by them but the vast majority do or are). So what the purists say doesn't have much impact on what commercially-available synthesizers can do, indeed have been doing since the first models, with varying degrees of success.
Sampling, of course, was a huge step forward. But it was also a huge step backward in that the subtle control of a sound and the connection between notes that were the hallmarks of many acoustic sounds were also lost. We've seen many technologies attempting to get those things back; huge key-switched sample libraries, Synful Orchestra, Super Articulation (1 and 2), Articulative Phrase Synthesis and SuperNATURAL Acoustic to name some.
But can any technology actually get us all the way to essentially "perfect" emulation of acoustic instruments, especially as controlled by a keyboard? For some of the less challenging I think we are already there but for some instruments - the solo violin comes to mind - I think it might be just about impossible (except in certain controlled musical passages).