As a fraction of total world GDP it is true, relative to the efficient markets hypothesis, that expected inflation must always be 0 and there can never be expected appreciation (or depreciation) of any asset.
No. Suppose we are in a zero-growth economy. If an asset is worth $98 today and is expected to be worth $100 in a year’s time, people will only bid it up to $100 today if they are indifferent between $100 of consumption today and $100 in a year’s time. But people are (rightly) not indifferent, they prefer to consume today—hence even in zero-growth economies, you see a positive real, risk-free rate of interest. And nothing about the liquidity cost depends on a growing economy either.
No. Suppose we are in a zero-growth economy. If an asset is worth $98 today and is expected to be worth $100 in a year’s time, people will only bid it up to $100 today if they are indifferent between $100 of consumption today and $100 in a year’s time. But people are (rightly) not indifferent, they prefer to consume today—hence even in zero-growth economies, you see a positive real, risk-free rate of interest. And nothing about the liquidity cost depends on a growing economy either.