Skills and willingness to work for shitty companies. And they don't leave after 6 months even under abuse.
Don't agree with that part. When the market is tough, anyone is willing to work for shitty companies.
You missed out the main point that people on h1b have hard time leaving companies generally because not everyone sponsors h1bs, and the general process around applying for PERM and GC forces candidates to stick around for >1 year at least.It is a resource-protection mechanism for employers.
Adding to that the general incompetence by USCIS in handling h1b applications - where they take even 6 months to approve a h1b transfer.
Maybe stop abuse in the work place? Just a thought