Ramaswami is talking about an absence of skill in private industry, not academia (although academia suffers for the same reason). The reason why the US cannot even produce the necessary talent for private industry (or academia) domestically is because, while it is true as you say that anyone with a modicum of talent in STEM sleepwalks through US primary and secondary, as it turns out, the engineer who has only done maybe a couple thousand arithmetic operations in their entire educational career, and has never once touched any kind of formal proofs, is not actually going to be a very good engineer.
They might have a wonderful grasp of the theoreticals (the failed Common Core curriculum was a great fan of teaching huge amounts of 'advanced' material with absolutely zero practice attached to the learning), but they can't apply anything.
The reason why the US produces such people? Because there is no value put on education, and hard work in school. Sure, the finance 'industry' siphons off what little mathematical genius the US manages to produce, but 50 kids a year can only do so much even if they don't go into finance.
Private industry (and academia) is very much a work of the educated masses, which is why China is doing so well: huge numbers of well-educated engineers, scientists, and mathematicians. Same reason why US now lags behind in the fields that it doesn't already dominate: no well-educated engineers, scientists, and mathematicians. As the great George Bush once said: "The question must be asked, is our children learning?" The answer is a resounding no, and it's all down to culture.