I dont think it’s trivial at all, but exposed with a basic ui it could be a killer feature.
Hell, as a POC even simply saving everything internally on each “commit” could be a UX improvement, so you can move easily between “save points” of the project without going the “V2_final_forreal folder” route.
I'd be incredibly surprised if there is any DAW in existence that doesn't do this already.
But it has very little do with version control per se.
Ardour already has "snapshots" which work pretty much as you describe.
How so?
For clarity, my train of thought was that if you have that, you have easy differentiation.
Someone edited the transpose knob of a sampler plugin, someone else edited the cropping marks, you can take a shot at merging those differences.
Sometimes it might not make much sense - if you edit a synths preset, other people’s changes aren’t going to fit in the new one. But it’s a starting point at least.