An analogy
The CPU works like a conductor: one person, reading the score, making every decision, keeping the whole performance moving. Brilliant and flexible — but only one beat at a time.
Now look at the orchestra.
A hundred musicians, each with their own instrument, each playing their part — all at the same time. No one musician is more capable than the conductor. But together, they can fill an entire concert hall in an instant.
That is the GPU.
Not one powerful processor, but thousands of simpler ones, all running in parallel. Each one handles a small piece of the problem — one pixel, one calculation, one patch of the frame. Alone, they are limited. Together, they can render entire worlds in real time.