You do understand the comparison is pre-draft Andrew Luck to pre-draft Ryan Leaf, right? Before the 1998 draft, many smart people considered it a toss-up/pick'em between Peyton Manning and Ryan Leaf, some even feeling Leaf had more potential. Well, he got to the NFL and proved (and continues) to be a complete dumpster fire.
So, it's easy to look back now and say "ridiculous!" But the comparison isn't that ridiculous. No, I'm not saying Luck wouldn't be an improvement over Fitz. I'm saying Luck hasn't played a snap yet in the NFL, and despite all the best analytics in the world, the future is not always crystal-clear.