What is the mechanism responsible for the speed of light?
First of all, I've read almost all of the similar questions and duplicates given under them. And the question is never answered properly in any of them so please don't just share duplicates and leave it at that. The question is, is there a theoretical mechanism that explains why $c$ has the value it has? Is there a mechanism (even a proposed one) to explain this?
Before anyones says it, yes I would still ask this if $c$ was $1\frac{lightseconds}{second}$ ie. described in natural units. Regardless of the numbers and units we assign to it, speed of light has some intrinsic value. Whatever we define it to be, it takes 4 full rotations of Earth around the Sun for a beam we send to reach Proxima Centauri, which is about 4 lightyears away.
Yes, I know that speed of light isn't something unique about light or photons and that any massless particle in our universe travels in this speed. 187
This doesn't answer anything about the question, just a fancy way of saying "it just is". I don't even know why some users gave this as an answer in other threads.
$c^2 = \frac{1}{\mu_0*\epsilon_0}$ is not a proper explanation because
1) any massless particle has a speed of $c$, not just photons.
2) this relation is just a consequence of special relativity in its core, which has no mechanism explaining the origin of $c$.
This is just one of its assumptions which is validated empirically.
It seems to me that this is just an observation at this point with no known mechanisms behind it to explain it. If so, what are some likely and popular proposals for such mechanisms?
edit: People are once again trying to explain why the value of 3x10^8 m/s is an arbitrary one similar to 1 mile = 1.609344 kilometers. Once again, these numbers and units are of course arbitrary and are just tools to convey the idea. I am not questioning the value of 3*10^8 m/s. It could have been 42 sticks/mississippis or 1 ls/s.
Yet the amount of time it takes for a photon to travel from the Sun to Earth isn't arbitrary is it? 562