They just had the timing wrong. Unless you think the last ice age was truly the last ice age (Meaning no more!) then ok! However their have been many ice ages and they’ll be many more, it’s just matter of when.
It has been speculated that earth and mars had synchronous orbits at one time and may have traded spaces several times throughout the aeons.
Actually the last ice age hasn’t ended we are in a 22,000 year or so warming lull. The Quaternary is why we’re in now, a geologic time period characterized by cyclic transcontinental glaciations.