&'static references can be created in two ways: by hardcoding something - then it is not leaked, but stored as part of the program; and, yes, leaking memory, but it will always be explicit.
&'static reference guarantees that the object it points to is alive until the end of the program, yes.
It's not correct to speak about "dropping &'static str", since shared references are Copy, and therefore are never dropped (their destruction is just a stack memory deallocation). The value behind them, however, will not be dropped, even if it has drop glue, that's correct.