This is the legacy of the Arab Caliphate and the Timurids. All the Islamized countries were subordinate.
And no one was going to make them rich, they were only sources of labor and additional product. This policy is still alive to this day, so it is precisely the "centers" of the Islamic world that are flourishing.
And this is manifested not only in poverty. For example, the modern Uighuristan, that was previously a Moghulistan, the land of Genghis khan, does not even have protection from genocide in the Islamic world(except Turkey), and this is also not an accident: it was from there that the real Mughals came, who destroyed the Arab Caliphate.