That's true, but the 'high-order bit' in the music industry deals, back when Gates wrote this message, was that Apple had a comparatively dinky user base.

So for a record company to ink a deal with Apple was lower risk than with Microsoft.

Sometimes American fast food chains roll out a trial product in an isolated region, like a Canadian province. In 2003, offering music downloads to Apple users was a bit like testing a 'Baconator' burger with residents of Quebec.