And what exactly all games mentioned by You have in common? They are funded by platform holders to promote their hardware.
PC does not have platform holders yet still get games like Arma or Total War and one of the biggest budget titles like Planetside, Guild Wars or TERA.
Sure, the range of specs on PC is wast and lack of formalized specs, and a platform holder to fund something just to showcase a tech, means that moment to moment graphics experiences are lacking on PC, but it does not mean that it lacks big games or ambitious games.
Look for example at Planetside 2 or Guild Wars 2, one is pushing scale and tech, other is pushing content and scale.
Games on PC are budgeted differently, because they are not budgeted to showcase something, but attract userbase with gameplay.
Star Citizen main goal is not to push graphics technology and cinematic experience, even though its doing that and its marketed that way, but to make very deep space sim with tons of different mechanics. Fidelity is very important, is close second goal of the game, but mechanics and vast interactive world are prime.