There are two kinds of knowledge.
The first is knowledge gained through the sense organs and corroborated by extensions of the sense organs. This knowledge is gained by what is generally termed 1) the scientific method and 2) evidence. Both these methods involve the sense organs.
The second kind of knowledge is transcendental knowledge which is not gained through the sense organs but can be gained through the spiritual disciplines of yoga.
The knowledge of the Vedas was gained through transcendental knowledge and not through the academic or scientific disciplines (sense organs).
Historicity is a term used in reference to knowledge gained through the senses. It is not a term used in knowledge gained transcendentally. Hinduism is a belief in the Vedas as the revealed word of God. Knowledge gained through the senses does not fall under the purvey of Hinduism as it is not the revealed word of God. The ultimate goal of the Vedas (and therefore Hinduism) is to teach men how to realize God.
There may be from time to time apparent inconsistencies between the two kinds of knowledge. This is all due to Maya.
Sankaracharya said that all the stories in the Vedas did not have to be taken as factual, some were meant as parables to teach a lesson. Also understand that our view from the sensual side changes all the time also. What scientists thought was the nature of the universe 200 years ago is different from 100 years ago is different from now and will be different 100 years from now. Historical evidence has changed also during the same time periods.
Fulfill the aim of the Vedas; realize God in your own heart and ask Him directly why there is an inconsistency between the two. Until you realize Him directly there will always be inconsistencies; this is the nature of Maya. "Lectures are for the learned, not for Realization." - Sankaracharya