Because... the speed involved is conveniently far enough that no one is able to test it.
And once again you spout complete garbage.
It makes no sense at all to say the speed makes it far enough.
If it is speed it should be fast enough.
You do not need to set up a start and end point based upon how far it travels in 1 second.
You even provided an example of that with sound.
Notice how in that example they didn't set up a start and end point over 300 m apart?
Instead, they used a small tube to setup a standing wave, and used the wavelength and frequency to determine the speed.
You can do that with light, just like Hertz did.
Or, you can measure the direct travel time over some distance, and that time can be much less than 1 s.
For example, you can get a cheap Arduino with a clock speed of 16 MHz.
So if you can time it down to the clock cycle, that would be timing it down to the nearest 62.5 ns.
As we are now dealing with nanoseconds, it can be better to express the speed of light using nanosecond.
The speed of light is ~2.998e+8 m/s. This corresponds to 0.2998 m/ns.
So in those 62.5 ns, light would travel a mere 18 m.
So it would be fairly easy to set up a system where a radio wave pulse is transmitted, reflected, and returns, over a distance of 1 km or so, and time it using an Arduino, to measure how long it took and calculate the speed of light.
That 2 km round trip would take ~6671 ns.
That equates to ~107 clock cycles.
And that was just a cheap Arduino.
The processor in most modern computers operates at a clock speed of between 1 and 4 GHz.
a 1 GHz processor would be 1 cycle every ns.
In that ns, light would travel 0.3 m, or 30 cm.
So we most certainly CAN test it. Even you can. You just choose not to, because you know that testing it will show you are wrong, and you will have no excuse to dismiss your own measurement.
You are choosing to remain wilfully ignorant of reality and dismiss the evidence that shows you are wrong so you can cling to your fantasy.
in which case you would need to broadcast 24,901.461 mi/s (not 186,000 mi/s) to circle all the Earth instantly.
And more garbage.
An instant is not 1 s.
If you want to reach the entire Earth instantly, it needs to have infinite velocity.
The speed of radio waves is "fast enough". If I want to listen to a broadcast literally more than 12 hours away, it appears to be instant.
But not for things like RADAR and GPS.
With RADAR, if the speed of the radio waves were different, the distances calculated would be different.
RADAR functions by timing how long it takes for the wave to go from the transmitter, hit the object in question and reflect off, and come back to the receiver.
If radio waves were half the speed we thought they were, the distances calculated would be twice as far as they actually are.
This would cause massive problems.
Likewise, GPS relies upon the time delay from the signals being transmitted to them being picked up.
If the speed was different the position calculated would be wrong.
With that in mind, I guess the longest distance on Earth would be Howland Islands to Kirbati Islands?
No. Not at all.
The simplest way to understand this is to recognise that Earth is round, so it loops.
Being 24 hours behind is just being 1 day behind.
If you picked a location right near the international date line, it could be at UTC+12 or UTC-12, as they correspond to the same local time, just on a different day.
You could also do this by converting to degrees.
Each hour is approximately 15 degrees.
So 24 hours would be 360 degrees, which means you would be right where you started.
The greatest separation would be expected to be between locations with 12 hours difference (at equal but opposite latitudes, e.g. one at 30 degrees north one at 30 degrees south, or both on the equator).
That would be something like NZ to UK.
When accounting for speed from Wifi or phone data plans however, if there hasn't been actual progression of speed, then all these frequency adjustments and upgrades in range etc, etc, etc actually involve units per second. If frequency is irrelevant to speed of transmission of data, then there would be no purpose in adjusting frequency to levels that would be in the 5G microwave range. We could simply update working 3G connections and the signal should be as fast as light regardless, you say. Ditto for WiFi, just improve connections.
Continually spouting the same ignorance garbage will not help you.
This garbage of yours has been refuted countless times.
For an incredibly simple example, consider a 1 Hz carrier wave.
This is a wave which changes once per second.
If you tried to use a simple system of transmitting or not transmitting the wave, and ignore the higher frequencies induced by that, do you know what happens if you try and transmit a 10 Hz clock signal?
Some of the bits will be when the carrier is at a very low amplitude, and can easily be lost in the noise.
If you use a system where the "0" is actually a lower intensity signal rather than no signal, you also have the issue that some "0"s will have a higher intensity than some "1s"
But more importantly, you cut it up so it is now actually a 10 Hz wave.
If we do get into the more complex part of the higher frequencies from the square wave, you have a much higher frequency than 1 Hz.
You simply cannot cram an infinite amount of data onto a given carrier signal.
A more appropriate use would be putting a 1 b/s signal onto a 10 Hz carrier.
That this is not done, implies not all signals are equal, and that it is actually necessary to change frequency for reasons other than "we have a cool new thing and it needs to be at a different frequency than the lamer older things to not interfere with signals". In other words, if frequency is being adjusted to carry more data at faster rates, then not all speeds are equal. Or rather not all speed loads (the difference between a person running at 8 mph sprint and and the same sprint done carrying a backpack filled with 40 lb of books) are identical. I'm not actually sure which this is (actual speed or speed load), but the point being, either all electromagnetic frequencies are equal (sounds like lazy science to me) or the differences in frequency have practical value.
Not all signals are equal. A higher frequency, by virtue of being a higher frequency (and nothing at all to do with the velocity of the wave) allows it to carry more data in a given amount of time.
The speed being equal does not mean the signal is equal. It just means the speed is equal. And that is the speed of the wave, not the data rate.
No one has suggested that all frequencies are equal. We have just been saying that all frequencies of EM radiation travel at the speed of light.
Increasing the velocity of the wave would decrease latency, but it wouldn't increase data rate. Data rate is based upon how much data you can cram into the carrier in a given amount of time, not how long it takes that carrier to reach its destination.
Again, your delusional garbage makes as much sense as saying that because a truck and a car both travel at 100 km/hr down a highway, it makes no sense to use a truck, even though it can carry a greater load. That the only possibly way the truck could carry more and thus transfer more, is if it was travelling at a higher speed.
It is dishonest, delusional BS which has been refuted countless times.
And you are even now providing a similar example with a runner.
The "speed loads" i.e. data rate is not identical, because the higher frequencies can carry more data in the same period of time.
Each time you ignore this and repeat the same dishonest, delusional, refuted BS, you are just how dishonest, desperate and pathetic you are.