Amazon internal propagand emphasizes that Amazon is a startup. "It's day one!" is a phrase I heard way too many times. They have "door desks" -- which actually cost them more than regular off the shelf furniture would-- but they pretend like they're being frugal to perpetuate the perception that they're a startup. (When I found out about the door desks costs, I was sworn to secrecy, it is very important for morale.)
I think the result of this is that a lot of employees believe it.
I think people generally, want something to believe in.
If you give them something to believe in, and it seems plausible, and especially if its tied to their income, they'll believe it.
And they'll work harder for it.
It worked on me-- that's why I didn't just go back to sleep that night. That's why I stayed on for several months after that, until things became untenable for me. Hell, I was going to stay with the company, I had met the AWS team, had gotten an offer for a position there and was in the process of transferring, and only quit when that transfer was blocked!
In a way, "well run" could mean that you get a lot of work out of your employees, even if they are miserable. I think optimizing for employee happiness can help you, but it isn't necessarily the only way to have high productivity.
Google never actually claims they're a startup, they just say they want to be like a startup.
There're varying degrees of success at this, ranging from "if I squint really hard, I could almost see it" to "Yeah...I don't think so." But I give 'em props for trying, as most companies with 30k employees don't even make the effort.
BTW, I could go all the way up to the VP level within the Search bigwigs and they'd be able to answer this.
I have to agree with your last point. IBM is a "well run" company; they take very good care of their shareholders. Some of the things they have to do in order to take care of shareholders is one of the reasons why I no longer work there. But I still hold on to my IBM stock....
I think there are huge numbers of low level, new, or just... B and C level developers who come in to fill the ranks. A lot of the best devs at Amazon, when I was there, were indians who had to keep working at Amazon as it was the only way they could stay in America. I felt a bit sorry for them (and of course, from their perspective, Amazon might have been great compared to the alternative.)
This country really needs a damn visa for technologists, or something.
Anyway, at some point software development became a very popular career choice and so there is an endless supply of warm bodies graduating from colleges each year, all of whom know the Amazon brand and think working there would be really cool.