Why is Windows 8 a big failure?

After Microsoft announced that Windows 8 has failed to reach his goals all people start comparing windows 8 to Windows Vista.

No doubt that Windows 8 had officially failed, however windows 8 is actually way better than windows 7 but the problem is that people did see any difference between the two operating systems, in today's world marketing is very important, and why windows 8 failed ? because Microsoft didn't spent enough money to advertise the new system.

True, on the desktop, Windows 7 still ranks as the top operating system with 44.85-percent of all PC users, followed by the still popular Windows XP with 37.74-percent. Vista—yes the never-loved Vista—comes in at third with 4.51 percent. Despite the fact that finding and buying Windows 7 PCs has become increasingly more expensive and difficult, just try finding one in a retail store, Windows 8 share is growing but still comes in last at 4.27 percent.
Worse still, Windows 8's month-over-month growth rate is lagging further and further behind Vista's dreadful 2007 adoption numbers. When comparing the operating systems when they were first launched, Windows 8's adoption rate in its first month trailed Vista by just over half-a-percent among PC buyers. Now, in their 8th month out, Vista's market-share numbers now lead Windows 8 by 3.64 percent. Needless to say, both lag far behind XP and Windows 7's numbers at similar points in their product life-cycle.