Why do pianists who have more technique than many others practise more than these others?

Why have the Rothschilds more secretaries than I have? Because the administration of a large fortune entails more work than that of a small one. A pianist's technique is the material portion of his artistic possessions; it is his capital. To keep a great technique in fine working trim is in itself a considerable and time-absorbing task. And, besides, you know that the more we have the more we want. This trait is not only human; it is also pianistic.