Can metal chassis become defective? I

I have learned from a top repair technician with 45 years experiance that all internal electronic components can go bad after enough time (resister, caps,tubes) INCLUDING the actual metal chassis. He claimed that if an old unit is not working that you could replace ALL the electronic components and it still may never work because the metal chassis is WORN OUT. His theory is that the electrons that go into the chassis ground have (over the years) filled up the outer atomic orbitals and interatomic space with too many (used) electrons forced into the metal (aluminum for example) and that the metal is now defective for a ground chassis SINCE THERE IS NO SPACE LEFT FOR THE ELECTRONS. The metal is WORN OUT. It becomes a radioactive isotope of aluminum since there are excessive electrons in the outer orbitals, and unusable as an electronic chassis. If this is not the case then where do the electrons go if the chassis is not grounded to true earth ground (cold water pipe only)or through a proper three prong plug?