Why was America’s domestic labor market not able to respond to the economy’s need for technology workers ?

Since 1990, approximately 4 million unique foreign individuals have received H1B visas. A majority of these individuals work highly paid jobs in desirable locations across the United States. The jobs themselves are prestigious, comfortable, white collar jobs with ample scope for career growth.

My question is why did relevant domestic constituencies not respond adequately to the boom in tech sector employment.

Why did the population at large not seek training and skilling for these jobs ?
Why did education institutions not prioritize programs that would become pipelines to the tech companies ?
Why did the companies themselves not lobby the government to incentivize skilling in technology, and continue to rely on an expensive and somewhat risky source of labor ?