The first demand for most H1Bs is "sign back X% of your paychecks to us or go home" where X is closer to 50 than 0. The answer is very different depending on country of origin, ranging from "No way" or "I'll sue" to "yes sir, thank you sir." The first worlders I know kept their jobs and salaries. I doubt the same is true for non-first worlders.
There is definitely a stratification for offshoring with good people able to get better visas and/or salaries comparable to onshore employees. The number of good people is tiny compared with the size of the offshoring industry. Most offshore workers, certainly the ones working for large companies (onshore or offshore, i.e. Infosys and IBM) are salary ballast. They can bill but they can't do productive work.
Good people get good money wherever they are in IT (and some not so good people get good money). It is not like auto-workers with no skills (8 hours training) and no mobility. Companies that are "saving money" offshore or onshore are not hiring good people. Anyone with meaningful skills, even in India (a tiny proportion of those in India working in IT) will get offers at close to western salaries. A lot of people with no meaningful skills "edit a text file? I don't have confidence I can do that" will continue to be paid peanuts to do little positive work and, in many cases, lots of damage. Same as in America in the '90s tech boom where unqualified (and incapable) people were working because of the scarcity of capable people.