Dynamic linking is not the only way to deliver security fixes, just one particular, limited, C-oriented solution. Note that dynamic linking is also not sufficient to change C++ templates or C header-only libraries. It shifts all of the code replacement complexity from the OS (just replace a file) onto the language and library authors (ABI compat, fragile base classes, no inlining or generics).

Rust/Cargo gives you Cargo.lock (and more precise build plans if you want) that can be used to build a database of every binary that needs to be rebuilt to update a certain dependency. Distros could use it identify and update all affected packages. There are also caching solutions to avoid rebuilding everything. It's just something they didn't have to implement before, so naturally distros prefer all new languages to fit the old unbundled-C approach instead.