that assumes that you would have to "keep firing" people... which is unlikely. fire a couple malcontents and the rest get the message: nobody is irreplaceable.
HA! Good Fun!
You'd be surprised, not a general case, but sometimes the firing's backfire and you create more malcontents. It happened in my last job, company got mismanaged to death, team kept losing developers due to the manager's wannabe hardass-ness. Was funny to see them go from happy to describing to me how they'd cut the manager's throat, though, hehe (frankly a poisoned Jos Loius was the best option).