I feel cosmology ought to grapple more with, “Why is there something rather than nothing?” That question and this question are certainly linked. If expansion is a mirror of collapse, how do we get from some initial nothingness to a point where there is something capable of collapsing? Starting with an infinite amount of stuff everywhere feels like cheating.
But that’s cosmogony, not cosmology. Cosmology can just explore the cosmos that is there not having to worry about why it came to be. If there’s a causality of causality, then what’s the cause of itself.