Because it doesn't.
The Hebrew verb היתה translated "was" is in the Qal (indicative) perfect tense. It would have to be an Imperfect to be translated "became."
There may be some ambiguity regarding past or future actions, but that crops up only when the Imperfect tense is used, not the perfect.
It should be noted in this connection that the verb
was in Genesis 1:2 may quite possibly be rendered ‘became’ and be construed to mean: ‘And the earth became formless and void.’ Only a cosmic catastrophe could account for the introduction of chaotic confusion into the original perfection of God’s creation. This interpretation certainly seems to be exegetically tenable …” (
A Survey of Old Testament Introduction, 1974, p. 184).
In a footnote Archer adds, “Properly speaking, this verb
hayah never has the meaning of static being like the copular verb ‘to be.’ Its basic notion is that of becoming or emerging as such and such, or of coming into being …
Sometimes a distinction is attempted along the following lines:
hayah means ‘become’ only when it is followed by the preposition
le ; otherwise there is no explicit idea of becoming. But this distinction will not stand up under analysis. In Genesis 3:20 the proper rendering is: ‘And Adam called the name of his wife Eve, because she
became the mother of all living.’ No
le follows the verb in this case.
So also in Genesis 4:20: ‘Jabal
became the father of tent dwellers.’ Therefore there can be no grammatical objection raised to translating Genesis 1:2: ‘And the earth
became a wasteness and desolation’ ”.
The Hebrew scholars who wrote the Targum of Onkelos, the earliest of the Aramaic paraphrases of the Old Testament, rendered Genesis 1:2 with an Aramaic expression Dr. Custance translates as “and the earth was laid waste”. The original language evidently led them to understand that something had occurred which had “laid waste” the earth, and they interpreted this as a destruction.
The early Catholic theologian Origen (186-254), in his commentary
De Principiis, explains regarding Genesis 1:2 that the original earth had been “cast downwards” (
Ante-Nicene Fathers, 1917, p. 342).
According to
The New Schaff-Herzog Encyclopedia of Religious Knowledge, the Dutch scholar Simon Episcopius (1583-1643) taught that the earth had originally been created before the six days of creation described in Genesis (1952, Vol. 3, p. 302). This was roughly 200 years before geology embraced an ancient origin for the earth.
Perhaps the best treatment on both sides of this question is given by Dr. Custance in his book. He states: “To me, this issue is important, and after studying the problem for some thirty years and after reading everything I could lay my hands on
pro and
con and after accumulating in my own library some 300 commentaries on Genesis, the earliest being dated 1670, I am persuaded that there is, on the basis of the evidence, far more reason to translate Genesis 1:2 as ‘But the earth had become a ruin and a desolation, etc.’ than there is for any of the conventional translations in our modern versions”
"Strong's Dictionary of the Hebrew language "
"H1961. hayah, haw-yaw'; a prim. root; to exist, i.e. be or become, come to pass (always emphatic, and not a mere copula or auxiliary)...""
http://www.watchman-nee.nl/hayah.pdf
Your argument has been considered and found lacking. Read the above in depth. You need to THINK like an ancient Hebrew, not like a modern English Scholar.
"Remember what Martin Anstey expressed in The Romance of Bible Chronology. "When a Hebrew writer makes a simple affirmation, or merely predicates the existence of anything, the verb hayah is never expressed. Where it is expressed it must always be translated by our verb to become, never by the verb to be, if we desire to convey the exact shade of the meaning of the Original"