rhodes and guitars are more electroacoustic, the basic sound is not electronically generated. ok, I know even pure electronic instruments can be said to be electroacoustic since you need a loudspeaker to hear them.
emulating acoustics instruments with simple additive or subractive synthesis usually just sound bad - sometimes so bad it takes off and create its own niche (like a solina string machine or the dx7 glockenspiel).
emulating acoustic instruments is today done mostly with sampling. you record the acoustic instrment every third note (typically) from soft to hard … when you hear a big orchestra in low budget films/series today it almost always done with one of the complete sampled orchestras available on the market today.
In todays digital synths and software synths (just an app you install) the most common emulation is of the analog synths and drum machines of the 70s and 80s. not real acoustic instruments.
there is an area called acoustic modelling where you model the behaviour of wood, strings etc. in software but they are less common and more fun to be creative with (create models of stuff you cant build - really giant drums and so on).
The hard part is making these instruments expressive for those who actually can play. But you can always turn off this and make every note sound the same … there many in the business who cant play and this makes it easier for them.