> So they're legally required to buy out contracts if they want to get rid of a substantial number of workers in a short period of time

Sounds like you might be European. The US doesn't have contracts for salaried employees most of the time. In the event of a layoff, no notice is required, no mutual termination agreement needed, no consultation takes place. You are terminated (sometimes effective immediately) and if you're lucky you may get a severance package, which is not required by law.