The phrase "retain popularity" is correct and usable in written English.
You can use it when referring to something that is widely liked or admired and continues to be liked or admired over time. For example: The Disney films of the 1990s continue to retain popularity among fans today.
Mr Bouteflika served as foreign minister from 1963 to 1979 and retains popularity among those nostalgic for the glory years of the struggle for independence from France.
The following year he settled in the U.S. In 1889 he played in New York City the first performance of his Second Piano Concerto in D Minor, his most successful larger work, one that retains popularity throughout the world.
Although long scorned in more reclusive quarters as an anachronism, a benighted holdover from 19th-century Romanticism, he always retained popularity in corners of the repertory, specifically those involving the piano.
SA/SD increasingly abandoned in favor of Object-oriented Design (OOD) methods, retains popularity in the field of real-time systems to gain improved performance Finite State Machines (FSM), Data-flow Diagrams (DFD) and entity relationship diagrams (ERD) are unified within real-time Yourdon.
And these extremely red districts are some of the only places where Bush retains popularity.
Gradually, both the city of Toledo and its leader Juan de Padilla lost influence within the Junta, though Padilla retained popularity and prestige among the commoners.
Many varieties of wheat do not retain their popularity, and often those popular in one decade are replaced in the next.
No one really knows whether or not 3D will retain its popularity with British cinema audiences.
Yet he managed to retain his popularity through 10 different governments formed in the course of seven years.
