What you really mean is that there aren't enough people with the skills you want, willing to work for the salary you are offering. Increase the offering salary and you will find lots of qualified American citizens.
And there aren't as many Americans in IT as there could be, because the effect of H1B over decades has been to get smart teens to consider other fields instead.
We can’t even get to the point where we are offering a salary. Has nothing to do with it.