I just wonder what Google was thinking...
They were thinking, "Hey! We wrote the book on changing things that work well and that people like and are comfortable with just for the sake of changing things. But now Facebook is stealing our thunder! Must be time for another change!
It's pretty revealing that the answer provided in the thread you linked to included the phrase "...our efforts to provide a clean and simple
redesign of the search results page..."
What on earth could have been cleaner and simpler than the
original design of the search results page? IMO, it's become more distraction-plagued and confusing at every reiteration...