Gixer,
What you're not seeming to understand is that most people who play games on their PCs don't have a gaming PC or laptop. Those of us who custom build a gaming PC or buy an expensive gaming laptop are a minority of gamers and if any company who depended on PC sales, even Blizzard, was to target the level of PC you've suggested (2011 era gaming PC) as the minimum they would go under. In single player games or co-op multiplayer games graphics can be changed from very low to very high at only the cost of a bit of development time, but in a PvP multi-player game the cover objects (trees, bushed, hills, buildings, smoke, clouds, sun) must all be the same on all detail levels and this greatly constrains the range of graphics options available to be minimized.