God can do anything, there is no proof that He did. Subtracting from God's glory to have another sinless?
Do you believe somehow a perfect Christ must have to come from a sin stained environment?
Absent proof, that's what happened, how much more superlative is the act of the Incarnation, how much more a display of God's Almighty hand, how much more glorious that the Eternal God stooped to be born sinless man from sinful woman.
Strange ! I would think it would be even more Glorious that God would be born of someone who perfectly followed His will
Your analogy seems to glorify sin.
How can Mary being saved by Grace alone just like anyone else who is spared is saved by Grace alone be a problem for people who claim they're Christian and claim to believe in the Bible?
Mary was saved by Grace Alone, the only difference between Mary and anyone else is that she was saved by the Grace of God at the time of her conception rather later in her life. How is the Grace of God not the Grace of God? God didn't wait until Noah and his family were drowning to save them did He? God didn't wait until Abraham actually murdered Isaac and then revive Isaac rather than sparing him in advance, did He?
Time is meaningless to God and anyone who claims that God is bound to a timetable they're comfortable with is someone who doesn't believe in what Jesus Christ taught. God can bestow His Grace and Mercy on anyone He chooses at which ever point in their life he chooses to.
Someone who is arguing that God cannot do what He pleases whenever He pleases looks downright foolish when they claim that others are detracting from the glory due God the Father because they believe that God Almighty can and did bestow His Grace on Mary when she was first conceived as part of preparing the way for the birth of His Son Jesus Christ.
Mary and several other topics have always been something Protestants rely on as misdirection to keep people from focusing on what Protestants teach by by attacking someone else rather than defending what they teach. Naturally they try their best to distract others when the subject is Scripture Alone because Scripture Alone is so clearly contradicted by Scripture.
As anyone who cares to can figure out, though, now that most people can't imagine living without birth control pills, denying that Mary was saved by Grace Alone at the time of her conception has become more than a diversion. If someone admits Mary was saved by Grace alone at the time she was conceived, they're admitting that Mary was fully human as soon as she was conceived. If Mary was fully human as soon as she was conceived, then using contraceptives that work by denying an already conceived infant the means to survive is very, very, clearly murder and premeditated murder at that.
Far from being a diversion these days, denying that Mary was saved by Grace when she was conceived is the last line of defense for people who don't want own up to the fact that their personal self-gratification is more important to them than are the lives of infants.