If no one prayed, it would be a witness against us as children of God. God's will be done. But God hears His children. His children also care more about His will than their own. Therefore, what will be will be. But God does respond to prayers. But how can God respond to us when we do not ask?
And no, your logic is unsound. You say, "So that means that if you don't pray then you believe that god is going to let them die?" I say, the people that didn't feel compelled to pray are the very ones that did not care whether God would save these people or not. That means that the people that knew and didn't pray, these are proven to not care for those people because they did not believe God exists and is capable. As for His will, that is for what we pray. We pray so that we know whatever the final result is, that God's will has overcome at the end.
God wills that all flesh is saved. God has given us two options in life: to live or to die. Some choose death thinking that they are choosing to live; but those that choose life chose it thinking that they should die.
I understand your complaint, but you must understand that to our Father, you sound like an accusatory and rebellious child who stamps his feet when he doesn't get to prove that he should not have to answer to his father. But He gives you time to stop throwing a fit and to hear reason.
Now Jesus said that trouble is a necessity in this world. But He also said "but woe unto those through whom the trouble comes!" Trouble is a necessity because the flesh must be stirred up before it is willing to listen. The flesh has an appetite and it is rebellious against what is truly good. Now if the spirit of a man is at war with his flesh (not that he wishes to be, but because the appetite of the flesh desires that which the man knows is bad for the soul), then the spirit of that man is accepting of the lessons learned. But if the spirit of a man is in agreement with the flesh, then the spirit of that man will be angry when he suffers instead of learning the lesson on account of the bond between the spirit of the man and the flesh. Now the spirit of man is not strong enough to battle the appetite of the flesh all by itself. That is why we need the Spirit of the Lord. Trouble causes the flesh to suffer, for through flesh did the curse enter into the world. But God is able to save the soul, therefore do our spirits yearn for Him.
Now people say, "Too bad they didn't get to live a long life." I would rather that everyone got to grow very old, and hopefully not die, and instead live to see the last day and to be changed at the final trump. But, God knows better what is going to save His children. Therefore, whatever it is that will change the minds of the people He wishes to save, that He may allow - not because He wants anyone to suffer, but because He is trying to save them from the suffering of eternal banishment from the presence of the Lord. It is not out of selfishness the Lord does this, but rather He does it because He is ensuring that the next world within which we live, the perfect world, will have no corruption, so that therefore all of those who have true love will be able to get along without having to battle suffering and rebellion. There will be true peace, a holy peace, an everlasting peace that will never fail. Until that time, all of the spirits of men must be tried, and tested, and approved to be in His Holy Kingdom. Now if flesh is saved by danger, and it works, then that will He allow. Or if flesh is saved because it is treated, or healed, or granted holy pleasure, then that will He perform. Whatever saves His children, that will He do.
Those that rely only upon their own understanding are refusing to allow the Father to work through the lens which only He is able to see and we are not. Though He may share His vision with us, if we do not love him and we do not ask for it, then why should He give it?
It is because of our flesh that we are terrified and have sympathy for the pain of the flesh. But when Peter said to Jesus, "Far be it from you!" When Jesus said that He must be tortured and die, Jesus said to Peter, "Get behind me Satan, for you only care about the things of this world. But I care about the will of my Father that is in Heaven."
Now when a man says that he cares more about the will of his father more than his own security, then that is a brave and honorable and respectable and glorious man, do you not agree? So then why wouldn't you heed the words of the One who did these things, not because He understood that He deserved to die, because He didn't: But rather He did it knowing that WE deserve to die.
It's an act of insanity to the wise of this world. But it's an act of love to the wise of God.