Just like there is an acute shortage of NFL Quarterbacks that are capable of leading a team to a super bowl championship.
The problem with this skills gap myth is that we are looking for people who are better than most of their peers in the industry. The will always be a shortage of top 10% performers in the industry because the top 10% of the industry will always be the same amount.
EDIT: I should just clarify that I'm absolutely in favor of people coming from other countries to work in the US. That said, the H1B in its current form is often just indentured servitude and definitely needs to be adjusted. My statement is specifically addressing the skills gap myth.