[latchkey]

There is still a plan for that, but it has required a lot of R&D and 'invention' of new techniques. Read up on Verkle trees [0]. That said, the plan is to basically prune the database and not keep history of what each wallet balance was at a certain block. This storage is going to be pushed off to indexers that want to provide it as a service. I'm not sure that is a good or bad thing, but it'll enable the future you're talking about since we do not have infinite storage/bandwidth on our small devices.

[0] https://vitalik.ca/general/2021/06/18/verkle.html