You addressed the fact that there is no place we can look at in the universe, where this is not in fact something. You did not address the fact that the quantum world does not follow an arrow of time, nor does it follow strict causal links. You've ignored the extent to which I've said that there can be "causes" and "effects," but that doing so requires us to reconceptualize the terms to such a degree that it makes it inept in the Cosmological Proof.
Quantum Mechanics falsifies the conception of cause and effect being used to make the cosmological argument. Is that a better way to put it for you? It does not falsify the possibilities of cause and effect, but it does make the arrow of time you're relying upon, a very suspect thing.
Now you're simply saying:
We don't know or understand how some quantum events happen, therefore causality is challenged.
Again, this doesn't mean that the quantum event in question is uncaused, it merely means that we don't know how it was caused or what caused it.
Or if it was caused. And let me stop you right there, because this is exactly my point! I'm not saying there is not causation in quantum mechanics, what I'm saying is there is not any evidence to actually support causation. The burden of proof lies with you to
prove that there is causation, and to do that you need to deal with the
problems of radiation, and more generally, Heisenbergs Uncertainty principle. Without answering those problems (you've attempted to wipe the problem away, not actually deal with it), you are committing a logical fallacy, by appealing to ignorance.
And if you have an answer to those problems, I suggest you submit it to a Physics Journal, because physicists would be very interested in those answers.
That is missing the point in any matter; quantum fluctuations are events that are observed in the presence of space, time, energy and matter. They are observations, events, and properties of the universe and would not take place in the absence of existence of our universe (indeed nothing would). So it doesn't even matter whether quantum fluctuations appear to follow a non-linear concept of time because quantum fluctuations are observed in the presence of time and cannot take place in the absence of time, nor in the absence of space, matter and energy. This is why it is silly to claim that our universe tunneled into existence due to a quantum event; it would be like postulating that before anything existed - non-existence; nothing - the universe caused itself to come into existence. Yet that would be like saying that the universe caused itself to exist, which would require the universe to have existed prior to it causing its genesis of existence. Such a view is patent nonsense.
But you're still applying the conception of time, as in arrow, to even need a reason for what caused the universe. If time is linear, it needs an explanation. But time may not be linear, time may not be an actual "true" property of reality! Time may be as much a creation of the human mind as seeing the color blue is. Does "blue" exist? Eh, it corresponds to certain wavelenghts of the electromagnetic spectrum, but it's a far cry to say that this "is" "blue." If, as has been propositioned as possible (notice, that's not saying I give you a proof of this truth), the Universe is eternal, as in timeless, then it doesn't need us to falsely posit a cause to it - which is the same logic you are using as to why we don't need to posit a cause for God (which I have never said was false, I simply begged to know how you know this).
This is merely making a logical distinction between different types of existence.
For example, the existence of numbers or abstractions (for example "justice") are not caused to exist by anything. Surely you don't deny that numbers exist necessarily, do you? Nothing, for example, causes the number 7 to come into existence.
That's not true, it took a human mind to "cause" the number 7 to come into existence. It's a human conceptions, and part of the human psyche. There are many living things which don't have a real conception of numbers, it's evident in their actions, and we can even look at other human societies, and how they relate to numbers.
Which, keep in mind, is not me saying numbers of subjective, but perspective. They deal with a fundamental aspect of our Worlds, but they are still true because of our definitions of them being true, and how this is applied to the world around us. It takes a mind or a brain to take in the sensory data of the world, and only specific sensory data, and after that it still has to make a distinction between sensory information, in order for there to be anything like numbers possible. Again, the best example I can think of is color, where color points to something objectively there, but which is, in the end, also a complete fabrication of the human mind.
Why can't the universe exist necessarily? Because the universe could have failed to exist.
And you know this, how? Being able to conceive of different possibilities, doesn't mean those possibilities are true, or could possibly be true. To take an example from Hume, I can easily imagine playing a game of pool, and having the balls hit each other, and come off each other at angles other than right angles. Yet, from what we know, without changing the fundamental laws of physics, it is necessarily that billiard balls hit each other, making rights angles.
You're committing armchair philosophy, and it's the reason Bacon wrote about the Idols, and why we have the scientific method.