They only had one sort-of-a scoring drive, and even on that one it took a low percentage throw & catch on 3rd and very long. Then followed the QB dive "into" the end zone, after getting stopped on the runs. Your other two "drives" were the break-through-the-line run and the gadget play TD pass. Depending on those type plays to win in the NFL will get you few wins. Not without help. Sunday was a bad day for true football fans of the game.
They had three scoring drives, two were quick to score but they got the TDs, all revolved around Seattle's defense giving up big plays. And why couldn't Seattle stop them on 3rd and 28? Seattle got no big plays on offense, largely owing to receivers losing track of the sideline, and gave up 3 big plays on offense. That's a formula for losing a game. In a pit fight of a game where neither offense is doing a good job of sustaining drives it's going to come down to the big plays. Sure you don't want to depend on those plays every game, but sometimes you're going to have to. Seattle was in the same position as Pitt on that front, they too needed big plays to get big scores, and other than the interceptions (and really just the 2nd INT, the first one functioned mostly like a punt, Seattle got the ball at their own 16 which is probably where they'd have gotten it on a normal stop in those downs) Seattle just didn't get the big plays.