The issue is that it really isn’t prevailing wage.
A portion ($1500) of most H-1B application fees goes towards funding scholarship and training programs. This is called " ACWIA fee" - see [1] and [2] for details.
[1]: https://en.wikipedia.org/wiki/American_Competitiveness_and_W...
[2]: https://www.uscis.gov/sites/default/files/USCIS/Resources/Re...