my dentist also takes fridays off.... foiled my plan of using off fridays to schedule things.
My dentist is open 43hrs/wk.
Legally, 30hrs is full time for benefits, so it's hard to see any truth at all to anything you wrote.
Plenty of other businesses do hire lots of part time people and manage their hours in order to avoid obligations. If you don't think that is true, well, I don't even know where to start.
Medium/long term: Benefits really need to be a function of the government that taxes cover for all workers.
Health Care should be handled by a single payer.