The advocate of such a position basically does not need the existence of God to explain the origins of the universe. If God exists, he would be an even more detached being than the "watchmaker" god of Deists like Thomas Paine or Thomas Jefferson. For someone who is an atheist, a skeptic, or a believer in a supernatural being who is less than omniscient or all powerful, the evolutionary process and an old earth and old universe are necessary elements for his cosmology.
OTOH, a theist, one who believes in an all-powerful and omniscient God, would believe that this being would not control the development of the universe through whatever mechanism he chooses: fiat creation, intelligent design, or guidance of the evolutionary process.
The position held by mainstream science, that of random, unguided evolution, reflects the philosophies of naturalism and materialism. Because of these presuppositions, the position does directly address the origins of life and the universe. It is also in conflict with any theistic system.
Not quite. This has all been addressed many times before. You keep using the expression "random, unguided evolution." Mutations only appear to be random, because we can't predict them (too many variables), but they are determined by the laws of physics and chemistry. Natural selection isn't random either. The survival and reproductive success of various individuals is likewise determined by their ability to deal with their environment. It seems random, but only because of all the factors involved. In principle it's predictable.
Science does not embrace the philosophy of "naturalism and materialism." But procedurally, science has no choice but to work with the materials at hand. If you can figure out a way to verifiably work with spiritual phenomena, science will explore your evidence.