Why do you think it comes down to what Fiat Chrysler wants?
The market is constrained by the supply of batteries, and was even before the Coronavirus outbreak. It seems likely that they can't build many, and expect to sell what they can build despite the high price tag.
I've no doubt that supply is constrained for the cells/packs they are using. They want to price it high, and therefore want to sell less, no? How much it the current costliest Fiat 500? I've no idea, but I reckon the battery version must be €10k more.