I would imagine its a case of marketing/pr executives trying to justify their own petty, worthless existance. Whenever you see yet another pointless and crappy website redesign its usually due to a bunch of marketing people who realise that holding meetings with web designers and constantly redoing their online stuff creates the impression that they are actually doing some work; when they're not. All the while the original designers who worked hard and got the whole thing going in the first place have their work trashed, and then have to sit there trying to explain reality to these marketing morons, and then agree to make all the crappy changes so they can get paid.
Then 6 months later the marketing team blame the design team for the mess the marketing team created, allowing the marketing team to spend the following 6 months in planning meetings to fix the problem, where they all use big words and try and fake serious expressions. The result of the 6 months of planning meetings is to invariably recommission the same initial design team, who they then instruct to implement this wonderful new design the marketing morons have dreamt up. A design that is virtually identical to the one the web design team suggested to the marketing team in the first place.
This is happening all over the world, all the time, and something must be done!!!!!