Many do bury their miscarried children and even name them. However, to answer your question it has more to do with a culture which keeps telling women (and men) that unless a child is born they are not human and don't have the same worth. That is secular mankind's influence.
As you note 'personhood' is a subjective and in some cases a legal term and matters not in determining if one is a human being. That is handled by the obvious fact we are all human beings at conception.
Mincing words again shifting from the muddy waters of subjective philosophical terms. Do you deny the embryo is a human being and as such not a fact? Several (including yours truly) have pointed out the biology text books and embryologists who do confirm this is a settled science.
Therefore, if your argument is an embryo is not a human being even though the parents are human beings, then please posit your alternative science here.
If your argument is the embryo is not a person, then define personhood and when one achieves this personhood and why your definition is valid.
On legal personhood. Minors under a certain age are not considered legal persons, nor are those who are mentally handicapped. Are these children under the age of 16 in most states not fully persons because of an arbitrary legal definition?
Then there is the term moral person: A
moral person conforms to the accepted rules and standards of his/her society.
Morality refers to all people as human being.
As it goes even a zygote fits the above definition of moral person.
However, you want to stick with legal personhood. I don't think you are grasping what you are truly advocating:
In general usage, a human being; by statute, however, the term can include firms, labor organizations, partnerships, associations, corporations, legal representatives, trustees, trustees in Bankruptcy, or receivers.
A corporation is a "person" for purposes of the constitutional guarantees of equal protection of laws and Due Process of Law.
Foreign governments otherwise eligible to sue in United States courts are "persons" entitled to institute a suit for treble damages for alleged antitrust violations under the Clayton Act (15 U.S.C.A. § 12 et seq.).
Illegitimate children are "persons" within the meaning of the Equal Protection Clause of the Fourteenth Amendment to the U.S. Constitution. (https://legal-dictionary.thefreedictionary.com/person)
The phrase interested person refers to heirs, devisees, children, spouses, creditors, beneficiaries, and any others having a property right in, or a claim against, a trust estate or the estate of a decedent, ward, or protected person. It also refers to personal representatives and to fiduciaries.
There goes 'legal person' unless you truly think God gives souls to corporations like Amazon and Google.
What you are seeking is a philosophical definition of 'personhood.' One which where anyone gets to define when they think human life begins or a human being begins. As pointed out the settled science is conception.