Google is way to smart to have made the immediate change from search darling to search demon. It's my opinion that every single change they have made over the years since IPO, no matter how seemingly minor, has been carefully thought out and analyzed from an economic point of view. It's been incremental, a tiny tweak here, a bigger tweak there, but when you add it all up, it becomes major. There is a world of difference between Google pre-IPO and Google post Panda.
And this difference has had a single minded goal all along: Increase revenue to keep the stockholders & board of directors happy; and increase bonuses to keep the employees happy.
So the ads take up more room, and we see Google properties such as YouTube, news, maps, etc all becoming more prominent in the SERPs, with the result of pushing the organics lower on the page.
You want more exposure? Pay for it.
Because the changes happened slowly, it does not seem so manipulative or obvious, but think about Google then and Google now, and these accumulated changes won't seem so small. Candidly, it has all the hallmarks of a brilliant longterm business plan, a slight-of-hand that goes mostly unnoticed. It's not about being "good" or "evil" ~ it's about business, and business at their level is not a lovefest, it is war, and they intend to win.