A "free market" for labour would mean immigration, not temporary work visas with strict conditions. H1-Bs shift power from labour to management. Management is not asking for an immigration fast-path for highly skilled professionals -- they are asking for temporary permits. H1-B workers, while obviously benefitting from the program, are not seeing the kind of benefit they would if they could immigrate and if they could be hired permanently and progress in their careers in the US. The economy as a whole benefits much less from H1-Bs than it does from skilled immigration. H1-B holders who subsequently start new enterprises aren't doing so in America.
I realize that some H1-B workers are able subsequently to immigrate, but it's a separate route and it's not the program's intention. It's good to have a program that lets highly specialized advisors in -- it ensures knowledge and skills transfer from the broader world, but H1-B is not primarily used for that. The program would have more value if it had higher standards for quality, not larger quantity. As it stands, it's simply an attack on labour, one that cloaks itself in the language of freedom and immigration while providing neither.