Why did the Controller abandon pure science? Chapter 16 Brave new world
The main reason why he abandoned it is that he was going to get exiled and sent to an island. The powers that be in his day were upset with him just as he is upset with Helmholtz and Bernard.
But why were they upset with him? The reason is that pure science is too involved with ideas and thought. The government does not really want that. They just want people to produce technology that is pretty much like what they already have. But pure science does things like making people think. That is precisely what the society does not want.
Mond had left the island even though he would finally be able to go on with his science in peace because he had been offered a position in the Controller's Council where there was potential for becoming an actual Controller. He decided to give up truth, beauty, and knowledge in exchange for stability and happiness.