Unlike the West, the Roman conquerors did not bring a higher culture to the East than the locals already had. Therefore, Latin there never could supplant the Greek language. With the decline of the state at the end of the 6th century, Greek became ubiquitous. Since the 7th century, emperors have been using Greek nicknames, for example Constantine IV Pogonatus (i.e. the Bearded)
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.