Stats have their place and are a tool to help assess a players ability and impact in a game. They are like the combine in that they can move a player up on down in the draft but every GM and Coach and Scout all say they use the tape as their final assessment.
Let's see the same stats on Peyton and Rothlisburger and Rivers in their 1st 7 starts or so. Even then it's still just stats and they are still a tool to be used but not the final and best way to assess a player.
Are you sure that's the game you want to play? Manning and Roethliberger both started as rookies, so the most apt comparison is Rivers, who didn't start until his third season in the NFL playing behind a solid starter (at the time) in Drew Brees.
Rivers' first seven starts: 124 of 187 for 1330 yards, 9 TDs, 3 INTs, 7.11 YPA, 96.3 QB rating.
Clearly, Kolb is not Phillip Rivers. What about Schaub's first 7 starts?
Rookie year (2004): 1 start; 17 of 41 for 188 yards, 2 TD, 3 INT, 4.6 YPA, 35.4 QB rating.
2nd year (2005): 1 start; 18 of 34 for 298 yards, 3 TD, 0 INTs, 8.8 YPA, 112.1 QB rating.
4th year (2006 - 1st 5 games with HOU): 111 of 157 for 1299 yards, 5 TDs, 4 INTs, 8.27 YPA 95.47 QB rating
Total those first seven games scattered over four seasons and you have 146 of 232 for 1785 yards, 10 TDs, 7 INTs, 7.7 YPA, 88.4 QB rating.
So no statistical analysis places Kolb even close to these other two guys.