Many people do not have a well developed creation cosmology. Either they believe that the waters above the firmament are clouds or a canopy of water that used to exist high up in earth's atmosphere or they embrace the Big Bang cosmology and end up believing an old earth view.
Although the discovery of the red shift lead to a Big Bang cosmology whereas the discovery of the cosmic microwave background radiation cemented it as the prevailing cosmology among old earth uniformitarians, there is no need to reinterpret Genesis 1 so that it conforms to a Big Bang Cosmology. This does not mean that the Big Bang Theory and the Bible agree with each other. Remember that a little leaven leaveneth the whole lump and therefore a Big Bang cosmology is not really the means God used.