No they cannot, this causes issues with their perm processing. You need to find an employer that can sponser your greencard otherwise you are out of country in 6 yrs. So you not just have find an employer that will transfer your h1b but also pick up perm processing from your previous employer.
It is far far far away from 'freely'. Given the arbitrary nature of uscis processing people try to minimize their iteraction with the agency. No visa employee will attempt this risky move for a 10k salary bump.
You just need one perm and 140 approval. And most companies are ready to start processing your green card in 3-6 months after you start at the latest. It is not as convenient as getting up tomorrow and walking away. But, it is definitely not as dire as you seem to be.
No they cannot, this causes issues with their perm processing. You need to find an employer that can sponser your greencard otherwise you are out of country in 6 yrs. So you not just have find an employer that will transfer your h1b but also pick up perm processing from your previous employer.
More info here,
https://www.murthy.com/2019/12/26/how-a-job-changes-may-impa...
This is just one example.
It is far far far away from 'freely'. Given the arbitrary nature of uscis processing people try to minimize their iteraction with the agency. No visa employee will attempt this risky move for a 10k salary bump.