Simply because we have failed to recognize an entity's "personhood" in the past is not an adequate argument for continuing to do so in the future. Part of the American political experience has been its progress toward recognizing all human beings as persons.
No, we didn't "reject that construction." We amended the Constitution. Huge difference!
We amended the Constitution with the 13th amendment, that prohibited involuntary servitude. That meant that blacks could no longer be owned.
And we amended the Constitution with the 14th amendment, that prohibited the states from denying equal protection under the law to any "person." (Which the 13th amendment "turned" blacks into, because they could no longer be owned.)
There has been no comparable amendment to "turn" the unborn into "persons" in the eyes of the Constitution. Therefore, they have no rights...even a right to life...unless granted to them by the "several states."