What drive computers to be ever more complex?

Selection force in evolution

More complex/powerful computers better help their users survive (well at least they think so)==>Human users want more features, more computational power.

The short lifecycle of computers, enabled by Moore's Law, makes the competitive exclusion principle particularly applicable: products with better/more features quickly eliminate their competitors.

Then why many other artificats did not get more complex or add more features? For example chairs, clothes.

Computers are unique in their intended function: computing (information processing). They measure the world via sensors, which include human beings, and affect the world via actutors, which also include human beings. While chairs and clothes are limited by their specific intended function, computing as a function is universal and seemingly unbounded: this drives Moore's Law, which in turn allows more computing to be done given the budget, and allows cheaper and better sensors and actutors. Some notes are below:

Computers provide ways to make conventional artifacts more complex.