it’s not “massively favouring” large mammals. it’s just the metric they were interested in. it’s not disingenuous to select this metric. we’re not voting for president of the mammals.

the flat voltage curve is only really a problem for LFP which is not really used in smartphones due to low energy density

I’m not sure if there’s something specific you’re asking about regarding the age thing. presumably you wouldn’t ask “is having a kid a mistake” unqualified, the answer is obviously pretty unique to your situation. being 52 doesn’t categorically make it a mistake, but IMO it pushes it into that direction.