Comment by shagie

> The only way abuse of both visas can stop is if they are not tied to an employer, allowing free movement of labor.

https://www.uscis.gov/working-in-the-united-states/temporary...

    Changing or Leaving Your H-1B Employer
    Q. What is “porting”?

    A. There are two kinds of job portability, or “porting,” available based on two different kinds of employer petitions:

    H-1B petition portability: Eligible H-1B nonimmigrants may begin working for a new employer as soon as the employer properly files a new H-1B petition (Form I-129) requesting to amend or extend H-1B status with USCIS, without waiting for the petition to be approved. More information about H-1B portability can be found on our H-1B Specialty Occupations page.

    ...

    Q. How do I leave my current employer to start working for a new employer while remaining in H-1B status?

    A. Under H-1B portability provisions, you may begin working for a new employer as soon as they properly file a non-frivolous H-1B petition on your behalf, or as of the requested start date on the petition, whichever is later. You are not required to wait for the new employer’s H-1B petition to be approved before beginning to work for the new employer, assuming certain conditions are met. For more details about H-1B portability, see our H-1B Specialty Occupations page, under “Changing Employers or Employment Terms with the Same Employer (Portability).”

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Someone on a H-1B visa can change jobs as soon as the other employer files a form I-129 to hire them.