Why is there Something Instead of Nothing? Questions like why something such as X exists seem reasonable based on phenomenon we observe around us. Like we know from experience that it makes sense to ask why does this table exist. We can describe economic phenomenon, or the scientific components of the table, that resulted in this table. From these kinds of experiences, we formulated a vocabulary that helps describe things. The history of science in turn has given us insights into what kind of questions can be formulated correctly and how they can be confirmed when it comes to more complicated phenomenon. Not every formulated question is a good one, bad questions don't reciprocate actual answers. That really depends on how things in the world actually works, and we just have to take it as it is.
So far from what we can tell, there isn't any reason to believe that this vocabulary can be used to describe why does "anything at all" exists. Like what standard (what collection of experiences that inform judgment) can be used to differentiate between one state of affairs where the world that we know of is the way it is, and where none of this applies. There is no way to formulate and apply such standards, in the way we can use science and economics to explain tables. And if we don't have the set of experiences where we can make the necessary judgments, there isn't any reason to suppose the question itself is a meaningful one.
My own guess is further insight into cosmological questions will dramatically alter our notions of causality and temporality, so progress on judging the meaningfulness of the question can be shaved down without experimentation indirectly from tuning our vocabulary.