[outworlder]

> After that they are given the green card, which lets them work for any company.

I upvoted as this is a comparison a hadn't seen before. However, what I quoted is innacurate.

They can HOPE to get a GC in 10 years (for people from India), provided their current company agrees to sponsor it and goes through all the necessary hoops (the biggest of which is the PERM application). And it's not guaranteed, no matter how much work you've put in.

They are tied to the company, but they can switch companies if they find another sponsor. It requires a lot of effort and is far more difficult than just changing jobs, but it's possible.

L1 visas are tied to the company, however.