That's because the militants that Iraq and Afghanistan are up against are incredibly more aggressive and desperate. Daesh for example has an intense sectarian hatred for both the state and people of Iraq-not to mention the huge injection of support that they had garnered from sympathizers-so much that they used performance drugs to frenzy themselves during combat. You don't hear of TTP doing anything like so.
This kind of aggressiveness isn't present in TTP since TTP is more of a revolutionary movement (you can just see it in the name). They don't want to destroy as much as they want to revise things.
I would say Iraq is more experienced today than Pakistan in this regard. The Iraqi golden battalions have really made a name for themselves as one of the most hardened troops living today.