Why is there not the large cities in the southeastern part of the arabian peninsula

Because of the Arabian Desert, which is a great desert region that occupies almost the entire Arabian Peninsula. It is the largest desert area on the continent, and the second largest on Earth. Summer heat is intense, reaching temperatures as high as 130°F (55°C); on the other hand, winters are invigoratingly cool with temperatures of 10°F (-12°C)