Honestly, a car with a small urban autonomy battery with a system where the rest of the battery is on a trailer would be a pretty awesome system, but it would require some massive adoption and car manufacturers are just going with ridiculously large batteries and fast charging for two reasons: they can sell it for more, and fast charging wears out the battery faster and requires more proprietary maintenance as a result.

A lot of EV innovations that could have been have been denied entry suspiciously when they've reached the bureaucratic industrial standardization that most major car manufacturers just seem to be able to gloss over. The car industry doesn't want to see the profits from proprietary parts and maintenance go, and nothing beats a combustion engine for that. I still miss the Sono Sion, an EV with solar panels which would have been perfect for people who use their cars occasionally on the weekend and rental services. At least Aptera is still going strong.