I think it’s worth noting that, for predictions concerning the next few decades, accelerating growth or “the god of straight lines” with 2% growth are not the only possibilities. There is for instance this piece by Tyler Cowen and Ben Southwood on the slowing down of scientific progress, which I find very good. Also, in Chapter 18 of Gordon’s book on “the rise and fall of American growth”, he predicts (under assumptions that I find reasonable) that the median disposable income per person in the US will grow by about 0.3% per year on average over the period 2015-2040. (This does not affect your argument though, as far as I understand it.)
I think it’s worth noting that, for predictions concerning the next few decades, accelerating growth or “the god of straight lines” with 2% growth are not the only possibilities. There is for instance this piece by Tyler Cowen and Ben Southwood on the slowing down of scientific progress, which I find very good. Also, in Chapter 18 of Gordon’s book on “the rise and fall of American growth”, he predicts (under assumptions that I find reasonable) that the median disposable income per person in the US will grow by about 0.3% per year on average over the period 2015-2040. (This does not affect your argument though, as far as I understand it.)