No, they're not. In the Western world, this is mostly an American thing. In most Western countries, there's a major responsibility for the employer to prove there is no other way before getting permission to fire someone.
Now there are all kinds of downsides to that, and it's far from ideal especially for start-ups, but I do like the way it doesn't tolerate the immature, irresponsible and downright immoral behavior towards employees that's regularly on display here on HN and considered "normal".
The cop-out of "this isn't working out, you're fired" borders on infantile behavior on the level of "I don't wanna play with you anymore". Firing people can have a devastating impact on the lives of the people it happens to.
Firing people should not be that easy, and in most civilized countries it isn't.