>The Linux kernel is quite complex but each part of it is well understood and there are a lot mechanisms in software to reduce complexity.
Well understood by experts, as is the appropriate section of the financial system. You chose to learn about the kernel, someone else chose to learn about asset backed securities. The guy who learned about Bach probably considers both to be very complex.
I have to say that the complexity of finance is more like the artificial complexity of Java EE, a regular developer can get a grasp of the Linux kernel by reading "Operating System Concepts", finance is more like a AbstractSingletonProxyFactoryBean.
Well understood by experts, as is the appropriate section of the financial system. You chose to learn about the kernel, someone else chose to learn about asset backed securities. The guy who learned about Bach probably considers both to be very complex.