My experience like all lawyers is in the end limited and limited to my clients and cases but I can tell you that for my corporate clients looking for talent, salary is usually the least important factor, meaning that they are not looking to pay the least but to find the best employee or at least a highly qualified employee. The competition for talent seems so fierce that my clients do not seem interested in lowballing great candidates. Now this might be limited to the high-end/"white collar" H-1B jobs, as you note above, and not the entry-level/grinder jobs.