You could be correct about four years from now, but by then I may not be using these programs professionally at all. I am not at all sure there are features of CS6 I will use, but I suspect Dreamweaver will have the most effect on my work, as web standards have changed so much in four years.
Seems a bit like the arguments for/against auto leasing. If one always wants the newest and shiniest, leasing may be reasonable. I have always purchased cars and driving one that is now 12 years old is just fine....