What makes it impossible?
You might suggest refactoring, which is what companies do too. They create departments, promotion ladders, org charts, and mission statements. The problem is that abstractions leak by design. As your abstractions accumulate and change outside your view, your ability to understand the entirety reduces.
If you have such a code base and you hire people that are not equipped, either through inexperience or capability, of managing that code base that is a resourcing issue.
If your executives cannot understand and control the organization they are tasked with controlling and cultivating, then they should be fired.
Which is basically what this dude is getting at.
And most importantly, humans are more complicated than code. With enough time and knowledge, I can accurately tell you what any piece of code does on a single expression or statement. Humans regularly do things they don't even know for purposes they don't understand.
The same thing regularly happens with smaller companies or code bases. The size exacerbates the issue, but it's not the cause of it.
Which is largely this OP's point regarding the subject of calling out culture rot and a particular executive.
So controls and processes are put in place to ensure no bad outcomes are possible, but this also prevents good, innovative outcomes from sprouting.
Fundamentally, it's a loss of trust that can exist in a smaller organization.
That dude just made the number up.
A startup starts at the bottom. It begs investors, customers, and employees from a position of optimism and humility. The organization enthusiastically changes itself to find a good balance between those three or it dies. As the organization grows, it starts demanding everyone else change for them instead. Google's interviews are an example. Its famous customer service is an example.
Then we get to size and complexity. Thanks to Dunbar's numbers, we know that there are numerical limits to a human's ability to know people. This makes sense. I can know everything about 6 people, most things about 50, and keep track of about 250 well enough. As the organization grows, your ability to know it disappears. You begin making abstractions. Instead of knowing exactly what Susan does, you say she works in X Department, for Y Initiative, doing Z position.
Google is so big that one person can't understand it anymore. The inevitable reduction to a corporate abstraction occurs and then people treat it like the X Company, which is just like Y Company but makes X instead of Y. Short term revenue and expenses are the only measures at the end.
And in this faceless abstraction, the professional parasite class infests and extracts resources and morale. Eventually the C-suite stops fighting it and joins in on it until only the sheer size and momentum of the company keeps it going. Maybe an investor group will come and force a rework of the company, but not before the company is just a shadow of the shadow of its former self.