Anything that can make it into the code base will make it into the code base, given enough time. Of course, most possible code bases do not address whatever problem it is meant to solve; most possible code bases just crash, much less solve any problem, much less a specific one. Maintaining an active code base so that it continues to solve the problem despite its execution environment constantly changing is a form of entropy reduction, and that requires free energy to be added to the system.
The energy we spend on our code can either be in the form of human attention, or electricity-powered automated analysis.