No sense to whom, you?
Matthew 1 says nothing about Mary's relations with Joseph after Christ was born. The firstborn is a firstborn even if he remains the only male child, it is a legal status. "Till", Greek "eos", is often used in the sence that refers strictly to the past without reference to the future, like in "the field was called Haceldama, that is, The field of blood, [eos] this day" (Mt 27:8).
In the economy of salvation, Mary giving birth to others would give a dubious status of Brother of God to the putative sibling; it would also signal that with mothering Jesus her work was somehow not gloriously complete. It would also conflict with her adoption of, and by, St. John (John 19).
Which would have created a de facto royalty that could have very possibly continued to this day with people claiming to be direct descendants of God's siblings.
Correct. And here we have another English-language bible only misunderstanding. The Greek term is really closer to until.
There are numerous biblical examples that show this beyond any doubt. It would also conflict with her adoption of, and by, St. John
In fact, it would have been illegal.
Matthew knew them both. Had he meant the viginity was permanent, he would have indicated that. He would have extended the "till" beyond the birth, as he did with the field of blood. As it stands, Matthew simply noted the birth as the limit, not some future event. Matthew never noted "perpetual virginity" even though he knew them both well.
"In the economy of salvation, Mary giving birth to others would give a dubious status of Brother of God to the putative sibling;
Not in the least. Unless Mary was God's wife, which she wasn't.
it would also signal that with mothering Jesus her work was somehow not gloriously complete.
Not gloriously complete? Mary was Joseph's husband. Luke 2:48-50
When his parents saw him, they were astonished. His mother said to him, "Son, why have you treated us like this? Your father and I have been anxiously searching for you."
"Why were you searching for me?" he asked. "Didn't you know I had to be in my Father's house?" But they did not understand what he was saying to them.
"It would also conflict with her adoption of, and by, St. John (John 19).
Not really. Joseph was dead. Maybe any bros and sisters were too, or being with John was better. It really never mattered to me if He had bros, or sisters and I can't say at this point if he did. The light through the window thing, I don't believe at all.