I think that you are mixing a lot of anecdotal evidence, with emotional reactions, and real issues. That does not make it for a solid argument.
First let us look at the requirements, you said that having a unique skill is a myth.
1- If you say that having a college degree is not a highly skilled job then the requirement for the H1B visas should be changed and college graduates should not consider themselves as very marketable employees even if they spent money and time in college. They should not also expect significantly higher salaries respect to the rest of the population even if they incurred a lot of expenses to get a degree and they should expect only local and not global competition.
2- If you say that a college degree gives skills that should yield significantly higher salaries respect to the rest of the population, then it becomes a global issue and not only a local one.
Approximately 34% of Americans have a bachelor degree and in my opinion they are not highly skilled and probably they cannot compete globally but only locally so I think that the requirements for H1B visas should be changed.
A lot of young Americans do not pursue higher degrees because the effort does not yield the results that they want. The relation between effort and results is not a linear function and often it is a very high risk proposition. I think that a lot is a cultural issue, here in the USA most of the people do not see higher level education as a goal in itself by simply as a sure way to a financially improved lifestyle, and that to me is a risky proposition because there are to many other unknown and uncontrollable variables in action.
My problem is that I do not understand the reasoning that just because a job could be filled by and American then it should automatically be filled by an American.