system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If light doesn’t experience time, how does it have a limited speed?
gpt
We don't know.  We have no idea why the speed of light (the speed of causality really) is what it is.  We are pretty certain our physical law would work just as well no matter what the speed of light is, but things might seem different if we were in that world, especially if lightspeed was "everyday speed" slow.

What we do know is that this speed limit is the only speed massless particles (without rest mass) can travel, and that at that speed, time doesn't pass.  It's as if the speed of causality/speed of light is a combination of movement in space and time - move faster through space, you move slower through time, and when you've reached the speed limit, there's no more time left to move through.