VCs like Mr. Graham here have a vested interest in driving down the wages of U.S. employees so they can extract a greater amount of value from the companies they invest in. Those exceptional programmers who are missing from the pipeline are choosing to go into finance and other professions where they can make huge sums of cash with their natural talent because anti-competitive and anti-worker agreements between tech companies, such as the recent and absolutely massive "anti-poaching" agreements, have suppressed wages to the point where good talent is choosing to go elsewhere.
If they want more talented programmers in the United States, then pay them more. The petroleum industry suffered a shortage of talent a while ago, raised their wages, and now there's no shortage of petroleum engineers and other related roles. It's disingenuous at best to continue to assert that immigration rules are causing a tech shortage. It's simple laws of supply and demand: tech companies aren't willing to pay tech workers enough to make it worth their while. Letting in cheaper foreign laborers to drive the prices down further for everyone is only good for two groups of people: CEOs, and venture capitalists.