Earlier quoted context omitted.
If you did that you'd favour profitable industries (say computing) over areas with actual shortages (say Arabic translators in Detroit). You'd also make it impossible for areas with low cost of living (Detroit) to be allocated any H1B visa. It's one of those perennial proposals that always come up but are really poorly thought out when you look into it.
If there were "actual shortages" of Arabic translators in Detroit as you suggest, market forces would drive wages up until enough people with the skills were sufficiently motivated to move to Detroit. In the case of a long-term, widespread shortage, rising salaries would lead to a widespread increase in people training to enter the industry. This is exactly what's been happening with software the past several years.
I don't know about the specific case of Arabic translators, but that's far from the only possible outcome. It's also likely that you won't find one at any price that your poor Arabic-speaking parents can possibly afford to pay to attend your parent-teacher conference meetings, and you end up with no translator at all.