I always thought replacement packs were the way they should go but with the efforts to build X number of additional packs for those who would benefit from swapping, that increases costs and use of limited resources. Then, what percentage of EV drivers would actually replace instead of just charging. EVs limitations become more visible as adoption increases: range, charging options away from home, resource requirements to build batteries, scalable recycling options, and impact of degenerative usage on batteries are some issues. I know that if I bought a 10 year old car I wouldn't think I would be replacing the engine. But buy a 10 year old EV and you may need to replace a battery pack at a $13k expense to have the range restored.
What I am saying is that I just see a different future for EVs than a utopian one where it is as easy to travel as it currently is. I am not saying that our past and current methods are ideal; decisions made by others in the past made mass transit a solution that would have financial and policy costs creating possibly insurmountable odds to overcome. So in looking for a replacement to power our individual modes, it is arguable that EVs won't be the only option. Perhaps history repeats itself and we move on electric cars. Again.