The other rationale I've heard is that if Apple paid for it out-of-pocket it could be considered anticompetitive for using predatory pricing. This circumstance

The other rationale I've heard is that if Apple paid for it out-of-pocket it could be considered anticompetitive for using predatory pricing. This circumstance, in which Apple essentially pre-installs the service on every device and subsequently offers it for free, isn't so different from 1990s Microsoft bundling IE with Windows to undercut Netscape.