She isn’t a “God” because all of her traits are not innate and immutable parts of her character.
 
She isn’t an authority by cosmic right. She is because the pponies have chosen to place faith in her.

Somepony pick up the phone because I called it >:)

BUT
 
B-BUT
 
MUH HEADCANONS

I’ve always felt Luna and Celestia were “gods” in the sense of the Greek Pantheon. They were fallible and were mortal in a sense that the only ones that could kill them was another god themseleves.
 
Though as the show is now they might be consider “gods” now. Time will tell.
 
@Tk3997  
“They were fallible and clearly had limits on their powers even in S1” Where and in what way did we see they had limits.

@Tk3997
 
Ok, I will concede that you have some good counter-points, especially this:
 
“Depends entirely on context for me, but if a creator clarifies or adds details to something in another source concerning their own work I tend to weigh that pretty damn heavily myself. Really I dislike in general the entire idea that fiction can somehow just be divorced form the process or people that birthed it. Fiction isn’t religion stuff that’s in a work wasn’t produced (supposedly) by some unknowable god. Writers have intentions, they do things for a reason and can be asked about them, and sometimes even change their minds.”
 
I stress that my comment was more about how major questions regarding the narrative should be answered in-universe. For example:
 
What is an “alicorn”?
 
The show specifically mentions that term in MMC, thus turning it into a major question, ergo should be answered in-universe.
 
To be honest, I don’t mind Word of God for minor background details, since their impact on the narrative is minimal. I only dislike it when it is being used to answer major questions in the narrative, and giving the writers a get-out-of-jail-free card to cover up shitty writing.

I think my major question would be does that mean that Alicorns get a drastically longer lifespan than other ponies who seem to, at least with Earths, seem to last well into a couple centuries?
 
Would remind me a bit of Unsounded, where one variety of people have a caste system on hair color. Darker hair lives longer but less magic ability where Platinum blondes have great magic but die in 30 years.
 
Or perhaps their magic and connection to the elements or something else extends Luna and Celestia’s lives.

@Ebalosus  
Depends entirely on context for me, but if a creator clarifies or adds details to something in another source concerning their own work I tend to weigh that pretty damn heavily myself. Really I dislike in general the entire idea that fiction can somehow just be divorced form the process or people that birthed it. Fiction isn’t religion stuff that’s in a work wasn’t produced (supposedly) by some unknowable god. Writers have intentions, they do things for a reason and can be asked about them, and sometimes even change their minds.
 
What they say can often be illuminating and informing of those works. Ignoring such things because they didn’t appear in the work proper has always struck me as rather daft and highly illogical. On the same level as morons that will tell a writer to their face that the book THEY wrote doesn’t mean what they say it does.
 
Although in this case it’s not like creator clarification was even needed, as no where in the series proper are Alicorns ever portrayed as god like. They were fallible and clearly had limits on their powers even in S1, but this didn’t seem to stop fanon much. The reason this keeps coming up though is that a certain segment doesn’t really seem to like the idea that Celestia/Luna/Alicorns in general are just beefy unicorns with wings. They want them to be more then that even though there was never much evidence they were and the more material was made the more obvious their very mortal nature became.
 
For various reasons though some people just aren’t going to like that so the whole god question is just going to keep coming up in one form or another until the end of the fandom.

“Then the one called Celestia is not really a god?” asked Twitter.
 
“Yes-and no,” said Faust, “If by ‘god’ you mean a benificent, divine creature, possessed of great powers, life span and authority over a race - then the answer is no. This is the generally accepted definition, but it is untrue in one respect.”
 
“Oh? And what may that be?”
 
“It is not a divine creature.”
 
“But it is all those other things?”
 
“Yes.”
 
“Then I fail to see what difference it makes whether it be divine or not–so long as it is benificent, possesses great powers and life span and has authority over its race.”
 
“Ah, but it makes a great deal of difference, you see. It is the difference between the unknown and the unknowable, between science and fantasy–it is a matter of essence. The four points of the compass be logic, knowledge, wisdom and the unknown. Some do bow in that final direction. Others advance upon it. To bow before the one is to lose sight of the three. I may submit to the unknown, but never to the unknowable.”
 
(with apologies to Roger Zelazny)

@gittonsxv
 
Not only that, but also non-canon, since creator intentions should never be considered a part of canon

@MonkeyDzyrax  
Well, at the time, one was a rock, and the other was in some time warpy thing.

@Background Pony  
Lesser ponies probably think of them that way and they don’t discourage it. Not even they’re above the lesson, “when someone asks you if you’re a god, you say yes!”

@Clopitor_the_Hydrogenous  
discord and king sombra say hey

These comments will only end in tears.

Living gods are a historical facts. Think Pharaos and other antic kings.

@Background Pony
 
That episode was after Lauren Faust left.
 
That’s probably why she clarified that she thinks of Celestia and Luna as being born as alicorns, but there’s a good chance that S4 might address their origins and possibly have a different answer.

@Background Pony  
From the pov of ordinary ponies, Celestia and Luna are gods.

@Background Pony  
For a Gone With The Wind reference.

@Background Pony  
Because she’s the most powerful being in existence.

@Background Pony  
because she had to say SOMETHING for the reference to work!

@Background Pony  
some people in our world thought some historical leaders were gods a long time ago

Then why did Rarity say “As Celestia is my witness” in ep. 31?

i find these questions to be redundant…