The fact is, buying cpu that will be obsolete in a couple years and rather wastefull.
Also, not everyone can afford to upgrade every year.
Also, i doubt your getting 6ghz. Their current architecture cannot do 6ghz and even if it could thermals would be like a nuclear meltdown.
Their next 10nm node is having clock speed issue so it will not be hitting 6ghz either.
And we may get more cores for same price by intel in the next couple of years, but why wait when you can get the extra cores for the same price now with amd?