Through continued speculation, man postulated a chief god reigning over all gods who controlled
natures individual phenomena. I many cases, the chief god was originally a god who had ruled a
specific phenomenon. For example, in the Greek and Norse mythologies the chief gods was the first
god of thunder.
The same is said of Yahweh or Jehovah in Judaism which both Christianity and Islam descended
from it and Islam calls it ALLAH. Yahweh was originally the god of thunder and later became the chief god of for the Jews. furthermore this God was eventually considered to be an absolute and
transcendental God and finally the only God, denying the existence of any other gods. This led to the formation of cosmogonies myth that god's will and work created the universe and all existence in it.
Thus, whether it is one God or many, they are thought of as the controlling forces of nature and
MAN. With the establishment of communities some gods became symbols of the power or supremacy specified groups to strengthen the groups authority.
Elohim is the name of THE God in Jewish scriptures and Ellahy is the name of THE God in the Christian scriptures (as Jesus was supposed to have called out on the Cross); Both of them Have the root to the word or name "Allah" or "Alleluyah". These names of God predate Buddha. Even Buddha has "ha" on the end of it which by sound sounds like "ha".
The variations in sounds come from the movement of man across the earth and the tong in which they spoke. (For example: How many of us have heard our own names mispronounced by others who come from different countries to our own country where our name was given to us; even by region in our own countries our names may be pronounced differently by different people; eventually the name and the spelling is also changed by others) (The mane Mohammad is spelled also Muhammmid or Muhummet or Muhammut etc.) Words and names are bound to have changed over the centuries of time. I believe that Even Buddha believed in Allah and was teaching the power of Allah from the beginning and eventually the people started worshiping the MAN Buddha (who was a messenger of Allah) in place of Allah or in addition to "The One God". Why else would God keep sending new messengers to the people of Earth if the original message was not tampered with or deviated from by the recipients? It is by succession that we see messengers come to us as our messengers are of the same blood as we are from our forefathers back to the first man Adam.
Now as far as become a Buddha: In the religion of Judaism Christianity and Islam we do have the same exact principal but we call it by what it is not by a persons name like Buddha. Think how it would sound if we said in Judaism one could become a "MOSES" or in Christianity one could Become a "JESUS" or in Islam one could become a "Muhammed". It sounds silly dose it not? there can only be one Buddha as there was/is only one Moses, Jesus and one Muhammed. (( WE, HOWEVER SAY, CORRECTLY STATE THAT ONE CAN BECOME A DISCIPLE OR A MESSENGER OR AN IMAM OR A COMPANION OF THE PROPHETS OR A RABBI OR A PROPHET TOO IF GOD OR ALLAH WILLED IT UPON A PERSON )) NOW THIS MAKES MORE SENSE THAT TO STATE THAT ONE CAN BECOME A BUDDHA OR A MOSES ETC. DOSE IT NOT? WE ALL CAN BECOME AS WISE OR AS BLESSED AS THE PROPHETS BECAUSE WE ARE OF THE SAME BLOOD AND OF THE SAME SPIRIT FROM ALLAH. IT ONLY TAKES THE RIGHT STEPS TO FOLLOW TO BE OF ONE MIND WITH THE MESSENGERS OF ALLAH OR ELLOHIM OR ELLAHY OR ALLELUYAH.