Over any timeframe, the rate of progress between the beginning and ending of the timeframe can be phrased as exponential for some exponent. It's just a matter of accurately estimating what that exponent is.

I take your point though - hypergrowth cannot be sustained - and estimating that exponent is fairly valueless if volatility is too high. This is all just math fun that won't be valuable if we bump along for hundreds of years and then all of sudden make a massive discovery.