There are two cases why companies would hire foreigners: 1. Hiring foreign workforce despite big supply of local workforce at certain skill level. It should be

There are two cases why companies would hire foreigners: 1. Hiring foreign workforce despite big supply of local workforce at certain skill level. It should be mediocre skill level with mediocre salaries because otherwise there would not be big supply of local workforce. The only reason why employer would do this is to reduce expenses for paying salaries. Wages for local workforce will decrease as a result of increased overall supply of workforce (locals + foreigners). 2. Hiring foreign workforce because of very small supply of local workforce at certain skill level. It should be pretty high skill level because demand exceeds supply and employers are willing to go through complicated visa process. Often such companies (like Google) are very hungry for talent and constantly hiring. It means that they would hire both, local and foreigners, anyone who is capable to pass their challenging job interview. Those companies are happy to pay decent salary for those rare talents. So this is background. Now, I will answer to your questions: If you cut the cap on highly skilled migrants, then temporarily salaries for highly skilled locals would spike, but in the long term such companies could not grow. As a result of this, some companies would go bankrupt (high tech is risky business, if you can't grow, often it means you will be dead) and some companies would go overseas. So in this case, either locals have less job opportunities in their homeland or they fly abroad to countries who are realized that high quality human capital is everything in global economy of 21th century.