Meters and seconds are not the only human units used to measure length and time. The value of 299792458 m/s is no more special than, say, 1802617757855.08 fur/ftn (furlongs/fortnight). read more
However c being close to 300,000 km/s does make things easier and there is probably a case for changing the definition of the meter so that c is exactly 300,000 m/s (or even 100,000 ft/s if you wanted to use a “metric foot”). read more
So, thanks to Maxwell and Einstein, we know that the speed of light is connected with a number of other (on the face of it, quite distinct) phenomena in surprising ways. But neither theory fully explains what determines that speed. read more