As if they had never prospered therein. Unquestionably, Thamud denied their Lord; then, away with Thamud.
The Saheeh International Quran Translation
كَأَن لَّمْ يَغْنَوْا۟ فِيهَآ أَلَآ إِنَّ ثَمُودَا۟ كَفَرُوا۟ رَبَّهُمْ أَلَا بُعْدًا لِّثَمُودَAs if they had never prospered therein. Unquestionably, Thamud denied their Lord; then, away with Thamud.