>Sure, if you attract them away from their current job. Then what happens to the company that had their employee taken away?

As a hiring manager? that is not my concern. But from a societal perspective, there are a few things the company that is outbid can do.

1. they can raise their own wages.

Note, this does increase the availability of workers through several mechanisms. most obviously, more people will enter the field as wages go up, but that takes a while. More immediately? you have people that have the skills who can also do another job.

For example, my partner does embedded linux development, mostly on arm. But, my partner could also do my job (I'm a SysAdmin) - and usually do it rather better than I am. Right now, the embedded stuff pays about 10% more than the sort of sysadmin gigs I can get, reflecting the required skills. But if there were suddenly more demand for SysAdmins? if you paid enough, I'm sure you could get my partner to take a SysAdmin job.

This is an important part of how Capitalisim allocates labor efficiently. Yeah, I could work as an apprentice motorcycle mechanic. I'm probably pretty good, I mean, for an apprentice. I'm not at journeyman level yet. If being a motorcycle mechanic paid better than being a SysAdmin? I'd probably spend the time and effort to get my motorcycle repair skills up to snuff.

2. they can train.

This increases the pool of workers rather more quickly than increasing wages. This is what I do when I need to hire technical people, and I can't afford market rates. Find people that you think have the attributes to do the job, once they have some help and practice.

From a corporate perspective, both of these things are just a matter of money. And so is going through the work to get a H1B.

>My point is that an immigrant isn't necessarily cheaper. I'm one of those immigrants on an H1B working in the US that isn't cheaper than an equivalent US worker.

Yeah, this hasn't been my experience. My experience is that outside of the contracting houses[1] or teams where you have a bunch of H1B types from the same place - if the same people that hired the Americans hire a single H1B on to a team of Americans, either the H1B is technically better, or he or she is willing to work a lot harder under worse conditions, or he or she is willing to take less money. Otherwise putting up with the paperwork and language barrier is not worth it.

It makes sense that someone working under a H1B would be willing to work harder; My understanding is that if you are fired, you have 15 days to find a new job or leave the country. Regardless of your financial ability, that sounds like a real pain in the ass.

[1]The only rational explanation for the high price and low quality of contracting houses that I can see is that someone is getting pretty huge kickbacks.

That company that lost an employee should have been paying them more. Any company paying below market rates will have problems retaining their best employees.