How do you represent that pool of strings on-disk?

If we concatenate the raw strings together without the null terminator, either all string references will require a length on top of the offset (25% size penalty for a Elf32_Sym), or we'll need a separate descriptor table that stores string offsets and lengths to index into.

If we prepend strings with a length (let's say LEB128), we'll be at best tied with null-terminated strings because we'd have a byte for the length vs. a byte for the terminator. At worst, we'll have a longer string table because we'd need more than one byte to encode a long string length and we would lose the ability to share string suffixes.

Out of all the jank from a.out and COFF that was eliminated with ELF, that representation for the string table was kept (in fact, the only change was mandating a null byte at the beginning to have the offset 0 indicate a null string). It works fine since the 1970s and doesn't cause undue problems, as nothing prevents a parser to spit out std::string_view instead of const char* for the application code.