As Millhouse said, that's the whole point of QB rating. To combine all measurables into one nice little neat number. Of course Nassib ranks high on a lot of cumulative statistical categories - he threw nearly 400 more passes than #2 on the all-time list (Graves).
To put this into a little more context, Nassib is the all-time Syracuse leader in passing yards - he needed 369 more attempts than Graves to produce 724 more yards than him. That's 1.96 yards per that number of attempts. That's really, really bad. And his yards/attempt average is 7.0, 9th all-time at SU just ahead of R.J. Anderson. This is a very underrated statistic, and speaks more to efficiency than any other stat.
And don't try to spin it as me saying Nassib was really, really bad. That's not what I'm saying.