Just so we're all on the same page here regarding numbers:
The SSME (Space Shuttle Main Engine) high presssure oxidizer turbopump produces 23,260 horsepower. The high pressure fuel turbopump produces 71,147 horsepower. That's just over 70 MEGAWATTS. There are also low-pressure turbopumps in play, and there were three of them per shuttle.
The Rocketdyne F-1 (Saturn V main engine) turbopump produced 41 megawatts. There were 5 in the first stage.
Still wonder why we don't use electric pumps?