I do remember hearing about deflation briefly in 2008, during the worst of the “liquidity crunch,” but not since. Isn’t the big threat over?

No. Remember, in 2006-2007, most people thought then that deflation was impossible. That’s when real estate peaked and dropped in half, commodities and stocks crashed 57%, and short term interest rates went to zero. Most people can’t see around the corner. We base our work on precursors of deflation, not the event itself. By the time you can see it, it’s too late.