Apple has never included the GPLv3 version of GCC on OSX themselves. For years they were shipping the outdated last GPLv2 release, and then they put all their effort into LLVM to replace GCC entirely because they refused to give up their DRM and Tivoization.

GPLv3 has this clause:

Some countries have adopted laws prohibiting software that enables users to escape from Digital Restrictions Management. DRM is fundamentally incompatible with the purpose of the GPL, which is to protect users' freedom; therefore, the GPL ensures that the software it covers will neither be subject to, nor subject other works to, digital restrictions from which escape is forbidden.

And has a definition corollary:

Complete Corresponding Source Code also includes any encryption or authorization codes necessary to install and/or execute the source code of the work, perhaps modified by you, in the recommended or principal context of use, such that its functioning in all circumstances is identical to that of the work, except as altered by your modifications. It also includes any decryption codes necessary to access or unseal the work's output. Notwithstanding this, a code need not be included in cases where use of the work normally implies the user already has it.

The GPL "stops" apps from using DRM because to use DRM is to violate the license and be liable for copyright infringement.

On OSX specifically, I imagine the Apple had some leaky GPLv3 code somewhere, because they open sourced a lot of Darwin between 2007-2010.

That's my point. The GPLv3 did less than nothing in encouraging reasonable sharing, it made companies wall things off more. When you're even a moderate sized company, there comes a point where it's easier to just write your own than to deal with the restrictions software licenses bring. It's happened with a ton of commercial code, and it happens with Free code as well.

Don't tell Blizzard that. They use a tons of free libraries in their flag ship products, including LGPLv3 in Starcraft 2. Im sure they would just love to delay the release date swith a year or two in order to avoid FOSS licenses and rewrite their own XML parser, fonts, or HTML/CSS code parsers.

That is, unless they can do cost-benefit. Some markets is just to competitive that you can't waste developer time in order to be afraid of licenses. The game market is very saturated, but there might be places where you can afford to entertain peoples fear.