You're kidding yourself if you think at will employment is used to just "fire slouches no questions asked". It's a gun to your head held by your boss. One wrong step and you're on the street. It's ironic that "the land of the free" is so keen to submit its citizens to such a tyrannical workplace.
You'd make a great union organizer with fear mongering like that. I've worked in a variety of places in a variety of fields, and I've never seen that done. What's more, the times when I have seen people fired they usually get a fat severance package that ends up putting a lot more money in their pocket than otherwise.
I'm sure that there are terrible places like that, but generally speaking doing business that way is much more expensive than treating your people well. When I was in management, turnover was one of the most expensive things to have happen. In some cases the people were irreplaceable (the experience and history they had in their brains was not possible to transfer). From time to time we'd have someone that just wasn't working out, but most of the time we treated people exceptionally well so they wouldn't leave and go to the startup down the street that pays more and keeps the fridge stocked with beer.
If things really were like you say they are, I'd be supporting unionization as well. However, in a couple years of management and a dozen or so as a grunt, that has not been my experience.
If we're gonna do anecdotes here I've seen management refuse to give a 5k raise to someone when they knew replacing them was going to be 40k minimum because "no one gets more than 2%", and I've seen that multiple times.
I've also been threatened before with concerns about my "culture fit" in a meeting my boss brought me into 5 minutes after I told him I disagreed with his approach but would do it if he said so.
I've had good managers but it only takes one asshole getting Peter principled above them to neuter most of their ability to run a team well
I have seen it quite a lot in software engineering in just my 5 years in the profession, happened to myself and many friends - hell, I was even in management last time it happened to me. Many times it came down to whether the people were a part of [insert manager's] inner circle/did whatever management wanted.
The stories are all too common, even at companies that supposedly treat their employees well. At will employment is a terrible thing.
