Why aren't Indians hired directly by U.S. firms? Instead, they are outsourced through third-party companies. I believe direct hiring would be beneficial for both employees and employers.

Another couple factors that may come into play is an organization's timeline and strategic imperatives. If they need the work done sooner rather than later or there's an end date (which could be measured in years), outsourcing tends to be quicker & easier. Organizations may hesitate to directly employ talent for work with a specific scope that's not part of their core business, regardless of whether it's domestic or international talent.   

Due to employment laws, it is critical to understand the hiring nuances and compliance risks that come with targeting international l talent.