This has very severe drawbacks, so it's not unambiguously desirable. Windows APIs are probably a mess because of this (also ignoring the fact that only company

This has very severe drawbacks, so it's not unambiguously desirable. Windows APIs are probably a mess because of this (also ignoring the fact that only company with extremely deep pockets can afford this approach). There is at least one extreme case where Windows had to keep a bug, because a certain program relied on it, and couldn't be made to work otherwise.