> That 4% you mention was less than 1% not so long ago and will be closer to 40% not too long from now. Such is the nature of exponentials.
But such is not the nature of the logistic function, which is usually a more accurate model of how technologies penetrate. (yes, in the beginning it looks like an exponential)
There is a final cost decline "baked in" to the curve, though. That's because the lifespan of solar now for calculations is maybe 20 years. Anything more would not make sense as costs are declining so fast. When the tech matures, the final part is extending the lifespan to 40-60 years.
But such is not the nature of the logistic function, which is usually a more accurate model of how technologies penetrate. (yes, in the beginning it looks like an exponential)