That idea is covered in the bottom of the article.

The problem is that it also biases towards much more senior roles.

One scenario we generally want to handle is: a person comes to the US, gets an advanced degree in a high-demand field at a US university... and then is immediately kicked back to their country of origin. H1Bs can help that person stay here and put down roots. But a fresh college grad is never going to be able to compete in a salary-based auction like you're describing, so pretty much all young, ambitious, well-educated people will get the boot.