Why doesn't Instagram have a native iPad app? It seems like an immensely profitable project that would take a relatively small amount of resources. iPad users

Why doesn't Instagram have a native iPad app? It seems like an immensely profitable project that would take a relatively small amount of resources. iPad users likely have a GDP bigger than France, I don't know a single millionaire who doesn't have one... yet their ability to click ads is very restricted by the mini/stretched screen. How does the culture allow so many non-core projects to get priority over this?