To be frank: The companies who abuse the H1B system are smart enough to hire people who are not typically hirable elsewhere, but which also are just about able to overcome their respective tasks.

One instance of this is: Hire someone who is not typically hire-able elsewhere, but encourage them to work an extra 30 hours a week, and get acceptable throughput out of them.

They can. It's harder than what it would be for a permanent resident, but they can, as there is a grace period.

Maybe you are thinking of L1?

There is no grace period when you're terminated from an H-1B. There might be one January 17th if it doesn't get revoked but right now officially you have 0 days to leave the country, no?

That's no longer true.

The new 60 days grace period rule has not gone into effect yet so it is still true at this moment.