It's not really that high of a power rating though

48V is ubiquitous through POE et al

And with 5A the gauge of the wire is important but it's not going to be running hot to the touch

I doubt you'll see it go much higher though, especially the current

Why not? It doesn't seem to be starting fires(At least not enough to make the news) and it's digital data, with IIRC pretty good forward error correction. Interference doesn't seem to be an issue, it all seems to work fine.

The only issue I see would be counterfeit cables, but that's the same issue you get with any low voltage system that allows separate cables, and 120VAC even has the same issue, people burn down houses with space heaters and extension cords incessantly, because we are apparently idiots who think it's fine to not have fuses in the cords.