Is that not how all continuous improvement works? Ground breaking innovation happens very seldom, rather improvement and tweaks are continuously made over time, often by different manufacturers, and each adds something to the previous incarnation....
a copy as you put it, is an exact replica of something, with no improvements, no changes, no re-design.... the Apeks harness system has many differences and what the manufacturer would consider "improvements" and in this way it is a "unique" design. It may share similarities, but then all SM harnesses of this category, share similarities, in the same way that many sets of Fins, or masks, or BCD's are very similar, this does not make them all copies of each other!