Two words: proprietary installers. If an installer expects to be able to overwrite a file and fails to do so, it might crash, leaving the user with a borked in

Two words: proprietary installers. If an installer expects to be able to overwrite a file and fails to do so, it might crash, leaving the user with a borked installation. Of course you can blame the installer, but resolution of the problem might take a long time, or might never happen, depending on the willingness of the vendor to fix it.