I think there should be a best-of-both-worlds type of linking - during compilation, the linker places a statically compiled library at a certain address, but doesn't include it in the binary. Then, during startup, the OS maps the same library to the given address (sharing the data between processes). This would improve memory use and startup time both and performance, avoiding dynamic linking.
Of course you need to match the exact versions between the compiled executable and the dependency, but this should be a best practice anyways.
Static linkers generally don't compile a "full copy" of the library. Just the code paths the compiled application uses. The compiler may have also made optimizations based on the apppication's usage patterns.
