Look at the C file API which most software is based on, it simply doesn’t allow it. Writing at a given file position just overwrites existing content. There is no way to insert or remove bytes in the middle.
Apart from that, file systems manage storage in larger fixed-size blocks (commonly 4 KB). One block typically links to the next block (if any) of the same file, but that’s about the extent of it.
Apart from that, file systems manage storage in larger fixed-size blocks (commonly 4 KB). One block typically links to the next block (if any) of the same file, but that’s about the extent of it.