I was always in love with the idea of [having the option of] not buying a battery when you purchased your car, and just join a battery swap club for a monthly fee, plus a per swap fee (or instead of a per swap fee, a mileage fee).
Then all the folks who rant and carry on about how much the battery will cost to replace one day would be silenced. Plus, you'd always have a non-degraded battery for the life of your vehicle.
I think the cost and complexity of the swap stations really made Tesla work hard to poo-poo on the battery swap idea. It truly would have been incredibly cumbersome to build-out, and expensive beyond imagination. It might happen one day - but only if one of these 2 things DON'T happen - 300 mile charge times fall to less than 15 mins OR range increases above 500 miles (most people rarely drive over 500 miles in a day so you essentially eliminate the need to charge while traveling, and even when traveling over 500 miles in a day, only a 20 or 30 minute stop would be needed, assuming today's charge times, to make a 800 or 900 mile trip in a day).