The first version of Pianoteq came back in 2006. There are apparently some exotic mid-90s synths with claims of being physically modeled too, don't know how accurate that is.

I currently use a raspberry pi with Pianoteq as sound output for my digital piano. It got a reluctant stamp of approval from my pianist son, although of course he prefers the physical response of even a poor acoustic piano.

Pianoteq is amazing with a good controller like a big Kawai VPC1 or the fanciest Fatar action in the Studiologic "GT" models. It is very responsive. I've been using it for over a decade and the sound keeps improving.

The combination of pianoteq and a sample based piano is pretty nice too, though tough to do on a Pi.

Good speakers improve the experience because you get your room resonance etc.

The coolest thing - you can change temperament. So if you are playing music from before equal temperament, you can hear what different keys used to sound like! Very interesting especially with Bach.

I agree with your son, there is nothing like a real piano. There are interesting attempts at combining the digital and mechanical with soundboard transducers from Kawai and Yamaha, I haven't used them but I would like to.

Pianoteq is more like spectral modelling. The sound lacks some of the movement and bloom of a real piano.

90s physical modelling was a very simplified modular kind of modelling. Instead of analogue oscillators and filters you had "string" models, "pipe" models, various resonators, and so on.

The models were interesting, but still quite crude and basic.

This project is the most physical kind of physical modelling. It's an unsimplified brute-force model of the entire instrument body and string system, in full.

It doesn't try to "model a resonator", it models blocks of wood with various holes, and calculates how they distort and radiate as sound passes through them.

It's ridiculously expensive computationally, but it's also the only way to get all of the nuances of the sound.

I expect they're already working on a stick-slip model for bowing.

Theoretically you could use the same technique to model a piano or guitar, and you would get something indistinguishable from a real instrument.

You'd likely need a supercomputer to run the model in anything approaching real time.

But the advantage is that once you've got it you can do insane things like replace the strings with wood instead of metal, or use different metals, or "build" nonphysical pianos that are fifty feet long and have linear overtones all the way down to the bass.

Do you have an analog sustain pedal? The fine control with partial pedaling made some difference for me re: pianoteq's feel.