This is a huge disagreement between us. If you loosen immigration in general, then you may have freer markets. But if you loosen them only in a narrow segment of the economy and while restricting mobility in others, you may end up creating severe market distortions that don't resemble a free market in any way.
If almost every country and profession had equally liberal immigration policies, then yes, I'd agree. But we're not doing this evenly, and I think this is why so many people who hold a favorable general view of immigration nonetheless object to these targeted visa/green card programs. As it stands, I think that adding a green card to every STEM degree (but not every JD, MD, MBA, DDS, etc) will end up creating market distortions that will probably just further deter US citizens from entering this field, amplifying the cycle of "shortages" and perhaps eventually creating exactly the "crisis" that the policy is intended to address.