Currently US educated STEM Professionals with Post Graduate degrees have a hard time applying for Green card. They have to depend on the mercy of employers to sponsor them.
Start up technology based firms would like to hire International STEM graduates, but often times they don't have the money to hire lawyers for the process. And other times they are just not willing to invest much time or money to sponsor these individuals.
Similar situation exists for Professionals with State Licenses to practice Engineering, but due to their short visa or temporary nature of visa, they are not able to stay in the US for long enough, and ultimately US is being deprived of their contribution to the development of Science and Technology, create thousands of new jobs for Americans.