That is because Allah never changes a blessing that He has bestowed on a people unless they change what is in their own souls, and Allah is all-hearing, all-knowing:
"Wancan ne, dõmin lalle ne, Allah bai kasance Mai canza wata ni'ima wadda ya ni'imtar da ita a kan wasu mutãne ba fãce sun sãke abin da yake ga rãyukansu, kuma dõmin lalle Allah ne Mai jĩ, Masani."