There's an argument that when the current s-curve (sigmoid) starts to reach its limit we start looking for other ways of obtaining improvements, such that over

There's an argument that when the current s-curve (sigmoid) starts to reach its limit we start looking for other ways of obtaining improvements, such that over time we have a series of sigmoids and overall exponential progress... until the final sigmoid. It reminds me of Malthus thinking the economy/world was doomed because we were about to run out of trees, and then we started making significant use of coal (coal had been used for a long time, but only on a small scale).