In the new software update of QuickTime, a new feature included is "Export to Apple TV". It gives the option of SD (Standard Definition) and HD. Since most people don't even have access to HD content (especially on their computers), some have come to the conclusion that Apple will start making HD videos available for download through iTunes. Would this hurt Sony and Toshiba with their brand spankin' new HD discs? Yes, because most people don't even have 1080P TVs. Of course this will change with time, but if Apple decides to also give the option, in the future, of downloading in 1080P, other major corporations (such as Sony and Toshiba) may be in deep shit. Think of it this way, would you rather buy a Blu-Ray player for $1,000, or buy a new loaded Mac Mini for $1000, which will do the same thing, and more.
Everything is becoming digitalized, there is no purpose anymore for physical media. The computer is becoming the entertainment hub for people. Computers will soon replace TVs' and other electronics in the home. If Apple does this, it will close the gap between TV and computer.
Now all Apple has to do is drop the Apple TV (I know it hasn't even been shipped to the general public yet), and incorporate all of its features into Macs.