[qeternity]

As someone with no experience in the domain, this sounds really interesting.

But one of the companies mentioned has been attempting this for 9 years.

Why hasn't this taken off already? It doesn't seem we're in need of any breakthroughs. So where do the economics break down?

[kristjank]

Precision manufacturing at scale. The physics of merging a hundred-gigahertz-scale circuit board track into a waveguide are very unforgiving. The physics governing the tolerances of said waveguide are similar.