>>41699454Gen 4, HGSS and Platinum explicitly detail how Cyrus discovered Rotom, thought it was clever to name it 'Motor' backwards after seeing it possess his toy robot, and then developed a specialized motor just for it and installed them into appliances. Then said appliances are later obtained by Silph Co. and an employee tells you about how they're working on using them as the basis for new tech.
Literally go play the games. Clemont may or may not have developed the Rotomdex, but he certainly did not create the engine that allows Rotom to live in it, and Silph Co. reverse engineered the tech first.
