Personally, I doubt that this is literal. I do not believe that such a bird actually, existed. It's more a representation of what the energy is about.
However, this does not mean that there wasn't a phoenix. From everything I've found over the past 20 years, I can only say that not only is the phoenix energy a very real thing, but it has very clearly manifested here.
There have been many people I have met who have either had an experience with this energy, or say they are the energy.
The story of the phoenix seems to be spread across the world and over the years. There have been many different names, but the general myth is intriguingly the same. It's always a bird that is reborn.
I can only suggest that while the story may well be a myth, there is truth to the myth, as all myths contain seeds of truth.