It's a finite quantity.. sure they can be split into many pieces, but something is worth what someone is willing to pay for it.. Take gold for example...
There is a fixed supply, and no one can change that, not even the real satoshi nakamoto (and we do not know if he is really alive or if he is dead/have ever existed)
But yes, they can be divided in other pieces, or just be forked, like it happened with bitcoin cash on the past.
Nowadays there are a lot of forks, but they are not the same, they are just for profit purposes, they are not taking the main "reason" of creating a fork, they are just using that idea to fill out their pockets, nothing more.
There is a fixed supply and no one is able to change that.
The community can possibly change that. A fork could increase the supply, technically, but doing that would be shooting ourselves in the foot. It's both impractical and unnecessary. If satoshis rise in value so much that they become unviable as the smallest denomination unit, then it makes much more sense to simply allow even smaller divisions.