I'm confused because Maru himself said that heavier geometry = RAM usage increase. A geometry heavy scene uses more RAM than a geometry light scene. I'm looking at this from a wider perspective than a single chair.
This scene is already very close to maxxing my RAM (64GB) when I render it, there are a number of models in the scene that use displacement where these 'artifacts' are visible. Let's say there are 100 different chairs, for examples sake. If the solution is to subdivide those 100 chairs multiple times until the artifacts disappear, then there's a high possibility I'm now at peak RAM usage and will start to suffer performance issues at render time. And I'm 100% sure that if I then started another thread to say I've got 'running low on RAM' errors, the suggested solutions would be to make the scene less heavy, whether that's in terms of texture sizes, poly counts etc etc but one of the first places I'd look to simplify/optimize is getting rid of unecessary geometry, hence the need for modifiers like ProOptimize etc.
The only evidence I have is that I've never had this happen with the old displacement. Imo that's enough evidence. Surely if the issue was lack of subdivision then the model would look crap without displacement too? If the model doesn't look crap without displacement, then wouldn't adding turbosmooth be classed as adding 'unecessary geometry' which takes you back to the optimizing point I made above.
As far as I'm concerned this is the still the same issue I highlighted way back when 2.5D Displacement was first introduced in Corona. I had a huge thread about it. I've been told it was fixed multiple times. I've proved it isn't multiple times, even on a flat plane.