Changing employees from employees to contractors was shut down here in Illinois several years ago. Targeted were those small companies who hand out samples in super markets. They were found to be evading state taxes, unemployment premiums and workers compensation premiums by calling their employees, "contractors".
A little after that, the state went after car dealers who were paying their sales people on a commission only basis. There were sales people who were not making minimum wage in the off season. It was ruled the dealers couldn't work the system that way and had to pay at least minimum wage every single week of the year.
Where there's a loop hole, government will close it and government will also close loop holes that allow companies to have a full staff of "part time" employees.
IMHO, no they won't. Obamacare was specifically set up to ultimately achieve socialized medicine (single payer). By putting the 30 hour requirement into the Bill, the Democrats knew companies would put most of their employees on part-time status. That achieves two things.
1) The company doesn't have to provide health insurance to the employee.
2) Without employer-provided health insurance, the "mandate" that everyone has to have have insurance kicks in (with a whole host of minimum coverage rules and mandatory "freebies" making the cost of the policy somewhere between $10-15k). Since the employee can't afford a policy from a private insurance company...say hello to socialized medicine.
Yes, the first few year the uninsured employee will simply pay the $2500 "tax" and gamble on his/her family's health (after the first year or two, the amount of the "tax" increases incrementally). When the uninsured need heart by-passes, cancer treatments, HIV treatments etc., with no insurance, the system will crumble and ... say hello to socialized medicine