Hardware

Depending on what games you run, extensive hardware is needed.

Newly created games have very demanding graphics, you need hardware that can handle those graphics so you have an easy gaming experience.
Usually, a good graphics card and processor are needed to run demanding games at high framerates. If you do not have hardware that can handle demanding games, your game with either run at a low framerate, or crash.

Most gamers nowadays also like to look flashy with their gaming setups.
RGB lighting on keyboards, mice, headsets, computers, etc... make you look like a serious gamer.