If they stood their ground, they could get somewhere. A hospital system losing 1,500 employees to a strike overnight would be literally catastrophic. There is no way in the world to replace that many residents in a short period of time. So... I guess the question to the residents is
Because if they push hard enough... Well, the hospital system literally can't afford to replace them all, but they might end up extending their training- it'd be a nightmare all around. Are they willing to live a nightmare based on principle and a small pile of cash?
I might do it for the lulz, but I'm nuts.