From Blair Hanley Frank:

Apple CFO Peter Oppenheimer said that the company is now changing the way it is accounting for revenue from the Mac to include providing free operating system upgrades over the life of the device, not just for Mavericks but for the future.

When asked why Apple decided to make Mac OS updates free, and make its iWork suite complimentary with new Macs, CEO Tim Cook said it was just what Apple wanted to do.

“Our primary reason for doing it … is we wanted it to become part of what it meant to own a Mac and to own an iOS device,” he said.

This is a brilliant idea! It reflects how mobile operating systems are transforming the entire approach of the consumer software industry. For Apple specifically this is a value add change that only effects a relatively small user base (compared to Windows PC) but none the less provides tremendous perceived value.

Conversely this kind of move could negatively effect Microsoft, as consumer sales of Windows  is still a sizeable chunk of revenue. I think strategically adding compelling value added portions to a free operating system could limit the issue of lost revenue. Additionally you would still see sizeable income from sales to OEMs.