No, that's not true. Capitalists make money from simply owning things, not because they're necessarily doing anything useful.
Can you elaborate on this? How can I become a capitalist so all my possessions start earning me money?
Capitalists make money from simply owning things, but that doesn't imply in the slightest that everything that can be owned produces income.
The classic example is a landlord: he collects income because he simply owns the land others need or want to use. He doesn't necessarily have do any work that's useful to anyone else, not even maintenance or "capital allocation."