theodp writes: It's not that Chunka Mui isn't impressed by the smarts of Instagram CEO and Forbes cover boy Kevin Systrom. Still, Mui can't help but ask, 'How Long Before Facebook Writes Off Its $1B Purchase of Instagram?' While pundits and analysts have almost universally praised Facebook’s acquisition of Instagram, Mui is less-than-impressed by Instagram's 80 million unmonetized mobile users. 'My prediction,' writes Mui, 'is that we’ll look back on the acquisition as a bust—much in the same way we now view News Corp.’s purchase of Myspace, AOL’s purchase of Bebo, and Excite@Home’s purchase of Blue Mountain Arts.' Ouch. Mui notes that according to a recent SEC filing, Facebook could ditch the deal by paying a $200 million fee if regulators block the merger or if Facebook terminates the agreement after Dec. 10, 2012.