I like the idea of swappable batteries in theory, but in reality... well... that's a lot of logistics and a lot of potential for things to go wrong. Consider the swappable propane tank market, for instance; it's clear that returning cans need refurbishment and testing before you can give them back out to people. This implies it probably can't be just done on-site at a gas station.
They also weigh an absolute ton, so specialized lift equipment is needed; they take up space and will be very difficult to move around. So, are we expecting to stock a huge pile of batteries somewhere with an automatic loader/unloader that can handle multiple people at once with a quick turnover rate that can put away a 2000 pound battery? It's just too much infra, compared to a charging station...
And then there's the matter of the vehicle design; chassis rigidity is important and batteries, being a huge weight, need to be positioned properly with enough load bearing structure around them to support this. I'm imagining a hydraulic lift raising a 2000 pound battery up into my car; some massive brace needs to be attached below it to hold it up. Talk about difficult to get right; we've got harsh conditions like road salt and rust to deal with, and we have to make a fully automatable fastening device that can work at a random gas station with any brand of car... yikes.
You're actually much closer to the idea with the reduce-capacity idea. I had a Ford Focus Electric a while ago that had about 80km of range on a good day. This was more than enough for 90% of my driving; my old SUV handled the rest. Net carbon savings were huge; pity it was totaled in an accident or I'd have kept it going. Even at almost 10 years old it still kept a charge no problem and was a delight to drive compared to a normal Focus. My current EV has far more range but feels heavy and ponderous despite nearly 500 HP.