It certainly has sufficient power and CPU memory - the X11 has been operating at <10 MHz since its inception. Of course, they did not support blending, smoothing, widening of forms, etc. Located at 600 MHz + and a modern graphics chip, the iPhone is a smoking monster.
Although Zingersoft provides, as Rob Napier said, an X server, so obviously it should be possible :)
groundhog
source share