Yes, because the 67 PAs are this season - what's on his mind currently. The past only tells me what his physical talents are.
There's different kinds of slumps. I'd not be worried if he was in a slump where he was hitting balls right at defenders hard. That'd be a bad luck slump, everyone occasionally lines out to the third baseman or hits a warning track fly ball - running a bunch of em in a row is a slump, but it's not a drop off of skill, and usually isn't a mental block (although it can become one). There's also the skill dropoff, where a guy getting older has lost a step, lost a little something in the wrist, and his home runs are turning into long fly outs, striking out on pitches he used to foul off, etc. That's Joyce perhaps - and it's concerning, but a veteran can adjust to it, at least to a certain extent, and still be productive, if not as awesome as he once was (that's Pujols). And there's the "the pitchers have figured him out" slump, when a hitter's weak point becomes exposed and regularly exploited.
What we're seeing on the field with Iannetta, however, isn't that. He's flailing out there, like a guy in the ocean who's forgotten he knows how to swim. Something is seriously wrong - he's either in serious physical pain that we're not being told about (in which case, go on the DL, get it taken care of, he's not doing any good trying to tough it out here), or he has a serious mental block. We're talking Brandon Wood territory here (and Iannetta never had BWood's physical talent in the first place!)
He isn't, skillwise, an OPS .297 guy. The comparison to history was to slow just how bad that number really is. If he can't figure it out, his career is over. Sosh is going to give him more chances to work it out than most other managers will (to our collective frustration), but eventually you have to release a guy if doesn't show any signs of ever getting it going.