Why does PC gaming exist since only a proper video card costs as much as a console?

Why does Mercedes exist, despite its cars being so much more expensive than a Chevy Aveo?

Better experience.

PCs offer better graphics, better user interfaces, greater flexibility, better performance, more expandability, superior ability to use mods in most games….the experience is superior in a number of ways.

Can you have a good game playing experience on a console? Yes, just like a Chevy Aveo can take you around town. But the gaming experience on a PC is much better.