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Yes, the revenues can fit an exponential curve (from inception to now). No, T==1, and is not being varied. But also, yes, costs also fit an exponential curve (except it's not being labelled as such). What you're arguing is the selective use of "exponential" to emphasize revenues over expenses, and you're not making THAT point clear. But this is also precisely why financial analysts care about things like return on equity, profit margin, net profit, net profit per share, etc.
Furthermore, the only thing we'd need to do to make sure rich people don't sit on their wealth is to simply institute a progressive tax system that takes a percentage of your wealth (not income) every year. (this is effectively what inflation does, except it's a flat rate and disproportionally affects the poor)