For sure - and I don't think we necessarily have the ANYONE part either :-) The reason for that is folks who build systems often leave, and the details of why or even how they did something leave with them. At some point, there's no one in the company who understands certain things.
And the analogy with biology actually goes even further - just like in software, we "know" the code (DNA), but how does that translate to the behavior of the complex system (and business requirements in software), is lost to time and the sheer complexity of these systems.
So someone builds something and they leave, and you can’t figure out their code? Or more importantly, you’re suggesting it’s impossible to figure out that code by anyone? Seems a stretch don’t you think?
he's not saying it's impossible to figure out some piece of code, but "all" code. There is just too much of it! Going into even something as relatively simple as an operating system, let alone a whole ecosystem with drivers, internet protocols & more would take many lifetimes.
The "anyone" part comes because there are countless parts of those infinately complex systems that have no documentation and no maintainers. They can individually be reverse engineered if it is needed in an individual case, but nobody is going to do that for most of them.
And the analogy with biology actually goes even further - just like in software, we "know" the code (DNA), but how does that translate to the behavior of the complex system (and business requirements in software), is lost to time and the sheer complexity of these systems.