If I remember right, he found that the GED was a good way of recognizing sound minds that had been too stormy to finish high school (prison population in particular), but that the social issues that limited some high-school dropouts' opportunities did not go away with this new certificate.
In the spirit of OP's main argument, there's room for a lot of cheaper/faster alternatives to college, especially for a lot of middle-skill positions. I like that part of the argument a lot. I'd just urge that we think harder about ways of helping candidates master the social/interpersonal skills that affect long-term success and employability. For now, it feels as if a face-to-face component is needed, too, beyond the technical skills that can be conveyed online.
Not sure about these days, but ~10 years ago, my friend's family's company did not require a high school degree. To your point, however, I know this because he specifically complained about dealing with under educated employees.
From some rudimentary googling, it seems requiring a HS degree is the norm, but there are plenty of cases of forgoing the degree/GED.