Back when I worked at Boeing, contractors got paid about double what the full time employees did. But, they received no employee benefits (worth about 40% of the employees' salary, if I recall correctly) and could be let go at a moment's notice.

So in the end it worked out about the same.

If the law requires contractors to get the same benefits, etc., the result will be the contractors will get paid less. The ones I knew wanted the higher pay / no benefits circumstance, and they'd lose that option.