Corporations are abusing foreign workers visas. These visas should be reserved for only the best and brightest in the world. When companies can bring in a dozens “Engineers” from India (about equivalent to our high school level education), for $30k/yr each, it only serves to weaken the salary of real US Engineers.
Supply and demand! If there is a shortage of X in the economy, then salary for that field will increase. This drives more students to move into those fields. But when we allow imported help at lower salaries, the opposite occurs.