What could be the reason behind decrease in quality and taste of Biryani in the Paradise restaurant of Hyderabad?

Hyderabad is a big metropolitan city in Southern part of India almost 600 km away from our city Bangalore which is also a big metropolitan city in Southern India. I have been to Hyderabad twice-once in 2015 and again in starting of this year 2023. Hyderabad is known for its biryani due to the presence of Muslims there. I ate in the popular Paradise restaurant there in both my visits there. But in 2015, when I ate the chicken biryani there in Paradise, it was just delicious and one of the best biryanis I have ever eaten. But in starting of this year when I again went to Hyderabad and ate in Paradise, I ordered the Nizami mutton Biryani there and even though it still tasted good, it didn't taste as delicious as the biryani I ate in 2015. Many other people I know also says that the Biryani in Paradise restaurant of Hyderabad doesn't taste as good as it used to before. Why?