So the manufacturing method i see that deals with th physics of the "wood binding" at the springs connection points is missed on these models.

The arm that extends to the connection point is not parallel with the wood pin. The helix ends "at the edge of the wood" and the arm then extends "out" in the tangent of the helix. Then, the connection point is a bend "past 90" to align with the wood slot.

This eliminates the physics of the bind. It is also a simplified manufacturing process easily automated. No "complex" bends.