> when you compare it with SolidWorks, OnShape or SolidEdge, there's clearly a huge gap in usability and capability

All 3 of these are using the same geometry kernel - siemens parasolid.

Most open source CAD software is using OCCT (cascade).

It’s the kernel that brings a lot of the capability. Check out “plasticity” (https://www.plasticity.xyz/ ) for an example of a single developers implementation of the parasolid kernel