Science is struggling to determine what dark matter is and in most cases people are assuming dark matter was formed during the big bang. It is my belief that dark matter is largely undetectable as the focus for the search uses techniques based on assumptions that our universe in its entirety was formed during the big bang. The thought that nothing existed apart from one supper dense ball of elements prior to this event is laughable. We already know that density of an object has little effect on neutrinos and our principle theory for dark matter is that it is some form of neutrino. It is also unhelpful to refer to dark matter as one thing or one type of element as we haven't discovered what it is yet. More likely is that dark matter is made up from as many or even more element known by us and is in as much abundance as the matter we know of. Until people are willing to let go of an out dated theory because it satisfies known physics principles we will never discover dark matter.
I leave you with a thought. Why do objects with mass have gravity? (Saying because we have witnessed it is not an answer). 2D physics will not solve a 4D problem!