If everyone plants their own fruits, the market actually shrinks. No one will buy or sell fruits because we all have enough. What matters for market/economy is

If everyone plants their own fruits, the market actually shrinks. No one will buy or sell fruits because we all have enough. What matters for market/economy is not how much stuff there is, but whether stuff is being circulated and money is being moved around. There's no economy for air because everyone has access to it. If for some reason the air becomes scarce, suddenly there will be a market for it and the economy will "grow". Official measures of economy are mostly about money moving around.