Data communications centres look at cabling as a 'commodity'. They will still want a product with the most performance and lowest cost ratio. Even though, it sounds like an elegant solution, thinner copper might be cheaper than regular copper, but it still might be heavier than an entire optical cable. There also is probably a limit in transmission speed, whereas, optical has upside, less weight, and more speed potential, I would think --- just guessing.

Now it still comes down to the lowest manufacture cost and with POET monolithically integrated it still would require less physical components and less physicality means less costs without compromising performance; in fact POET raises performance from 2 to 33x as per the THM meeting chart that was presented.

Monolithic