Why are they so resistant and *almost* never fails on it's own, being one of the most complex pieces on a computer and what does the most job in almost all situations? I am searching polls all around Google and the CPU is the least component that die (besides my personal experience in which none CPUs died).
GPUs are more complex but they are almost idle outside gaming, video, and 3D modeling.
Many thanks
Simple answer: CPU components are created at the microscopics level, and rely on material properties rather than physical properties to work. This makes them, functionally, the most durable component of a system.
Long answer: A CPU is a chunk of silicon, or other semi-conductor. It is etched and doped with other materials to make it into either a conductor or insulator. This process is either successful, or not. If it is successful, the material has new properties, which can only be destroyed if the material is chemically altered (through additional doping, burning, or other chemically changing process).
Everything else in a computer relies on both chemical and physical properties to work. Assuming that you do not have a basic understanding of electronics, I'll cover the basic components.
Capacitors - Conductor plates separated by a dielectric medium. This dielectric can be anything from oil to air, to glass. The dielectric constant of the dielectric influences the capacitors capacitance, and very small changes in the dielectric constant produce very large capacitance differences.
Diodes - Doped semi-conductors that largely only allow current to flow in only one direction. They have a breakdown voltage where they will not stop current from flowing, and always have a small amount of current that flows in the opposite direction, which is functionally nothing in simple calculations.
Coil/Choke/Inductor - A wire loop. These things are composed of wire wrapped around some sort of core. The core material matters a lot, but the biggest difficulty is finding out what the resistance associated with the wire is, and how this will influence the system.
Transistors - Doped semi-conductor that allows current to pass through only is a signal from another pin is present. These allow smaller voltage signals to control larger current devices.
Other IC - A varying combination of transistors, diodes, etc... combined into one package that performs a specific function.
The coil/choke/inductors generally never burn out. The ICs in a circuit also rarely burn out if not over-voltaged. Transistors and diodes fail, but very infrequently. They usually only fail when higher voltages are present, and the feedback in the system melts their shells.
What we are left with are capacitors and the boards themselves. Capacitors dielectric ages. Whether it be the heavy heating and cooling cycles, or the dielectric breaking down due to age, the dielectric constant changes. This negatively influence the capacitor, and will often partially vaporize the dielectric. If you've ever experienced this you'd either have the capacitor blow-up, or otherwise greatly swell. Then, we've got boom goes the capacitor, pop goes the circuit, and off goes the board.
The boards are even more fun. They can fail via heating/cooling cycles, pregnant traces, or simply poor layering. Starting with poor layering, the QC checks at the factory are basically to make sure everything initiallizes. The layers could well be intact and working there, but jostling during the long shipping process leads to layer separation. No contact=dead mobo. Pregnant traces appear over time. A minor deviation in the lead on the motherboard generates a point of increased resistance, which creates excess heat. The heat distorts the metal, and with continued heating the trace eventually pops. Pregnant traces are named because before they pop they generally create a bulge in the solder mask. Heating and cooling cycles are always an enemy. They create stresses in the board, which cause gradual failure over time. The only way to address them is to have an awesome cooling design to wick away all of the heat from your components. This is generally more expensive than just knocking a couple of years off your warranty...
So in summation; CPUs have maybe a couple points of failure. Motherboards, Graphics cards, and PSUs have thousands of points of failure. It doesn't take a genious to see why one fails more than the other.