All the charts on page 15. The ones where they extrapolate exponential improvement for a decade while only citing themselves. Their prediction is 15% annually for storage cost improvements in Li-ion batteries which they call ‘conservative’

Our analysis conservatively assumes that battery energy storage capacity costs will continue to decline over the course of the 2020s at an average annual rate of 15% (Figure 3).

Let us check if their souce updated. $139 for 2023? That isn’t a 15% decrease since 2019’s $156, let alone year over year since then, which would be under $90. In spite of last year’s drop that is still more than the 2021 price of $132. I don’t know what ‘on track’ means to you but it must be something different than it means to me.

Really gives me the warm fuzzies when someone looks at changes to physical systems over time then draws a trend line into the future indefinitely without any citations or discussion of plausibility for the part they drew on.

shouldn’t we rather invest our productivity and resources into a faster and cheaper solution?

We sure should. Do tell of this this faster, cheaper solution that is also adequate to meet all of our needs.

tow this line

https://en.m.wikipedia.org/wiki/Toe_the_line