In my experience - yes, this moral decay is a necessary part of the current corporate world. Or any corporate world. Or really, any world without the possibility of failure baked into it.
I've seen a lot of idiotic decisions made at Google, many of which have been complained about on Hacker News, many more of which are hidden causes of things that are complained about on Hacker News. In every case, when I looked at the chain of decisions that led to things being the way they are, every single decision was rational, given the information that all participants had at the time. There's no vast conspiracy dedicated to turning Google evil, no influx of incompetent new PMs & designers. Some of the most questionable decisions have come straight from old timers like Marissa, or even from Larry Page.
Instead, it's an information problem. Running any enterprise the size of Google or Goldman Sachs requires trading off many competing factors. To make the tradeoff, someone has to keep all that information in their head at once. There's no other way to balance competing demands; if you keep only part of the information in your head, your decision will be biased towards the part that you've loaded into your brain. If you try to spread decision making across multiple people, the decisions will be biased towards the part that the person who screams the loudest can hold in his head (which is usually a smaller subset than optimal; it takes mental effort to scream loudly).
I often see mystified posters on HN wondering why Google did something or other, and a good amount of the time, I know (but can't say) exactly why we did it. The userbase does not have all the information. Unfortunately, they don't care that they don't have all the information; they want Google to work as expected, and the fact that there may be internal systems that don't quite behave according to their mental model is irrelevant. And so the fact that decision makers make decisions based on information that users can't have becomes a liability in this case, biasing them away from what's "good" for the user.
I remember Paul Buchheit writing here, several years ago, "A system's participants don't have to be rational for the system itself to be rational", referring to market economies. I'd posit that the inverse also holds: a system with completely rational participants can still be irrational, if information flow between participants is not organized in a rational way.