The thing with static linking is that it enables aggressive dead code elimination (e.g. DLL are a hard optimization barrier).

Even with multiple processes sharing the same DLL I would be surprised if the alternative of those processes only containing the code they actually need would increase RAM usage dramatically, especially since most processes that run in the background on a typical Linux system wouldn't event even need to go through glibc but could talk directly to the syscall interface.

DLLs are fine as operating system interface as long as they are stable (e.g. Windows does it right, glibc doesn't). But apart from operating system interfaces and plugins, overusing dynamic linking just doesn't make a lot of sense (like on most Linux systems with their package managers).