What do we get if we look at say, FLOPS per US $ over time? This[2]. There is no reason to think batteries are any different, the only margin you have is to argue over which part of the curve you think we're in.
That FLOPS graph is an exponential scale... so that straight line "after the sigmoid" is an exponential growth curve. I'm not sure it makes the point you're trying to make.
have they?
'one in three' of all new vehicle registrations in china were electric last year https://www.iea.org/reports/global-ev-outlook-2024/trends-in... or 37% https://autovista24.autovistagroup.com/news/ev-registrations... and the absolute number seems to be doubling this year, though they only expect a 45% market share
these figures do include both hybrids and pure battery models, though
in general the 'experience curve' says that things get exponentially cheaper as you produce exponentially more of them