Electrical heating was supplied by the use of resistive heat radiant devices, and motors were controlled by resistive devices. Earlier generations of entertainment equipment ranging from crystal radio sets, with vacuum tubes to transistor radios and television sets were more tolerant of voltage fluctuations than today's equipment. Technology never stands still, every day something new comes along that is better, smaller, and more energy efficient. In the field of electronics, raced ahead of all other fields. Spaces between components are so compressed that damaging arcing will occur above 5 to 10 volts.
Damage can also result from lightning even miles away.
Even more sensitive chips are on the drawing boards. They recognized that certain power fluctuations could affect the operation of their products. Unprotected power can scramble your data, prematurely wear components, or destroy expensive chips. The studies and standards defining transient voltage surges have been available for many years. Yet today, many people view the existence of transients and their harmful effect with skepticism.