It doesnt matter where those guys were drafted... follow my logic.
If the Bills scouting staff has identified "QB X" as the next elite QB, wouldnt you want to ENSURE we get him? the only way to do so would be to draft him with #1 overall pick.
Would you wait till our 2nd round pick at 33 because Mel Kiper said he should be available there? what about the idea to trade down to say #9 in the first round because you think "QB X" will still be around at 9. but alas when our pick comes up at 9 some other team has already realized the value of QB X and drafted him before our pick no we missed out.
To spin this another way, think back to 2003. looking back would you have rather we traded up and gotten Phillip Rivers or Ben, or just been "happy enough" with JP ? how did that turn out? how many years did that set the organization back?
Can excellent QB's be found in later rounds? sure. is it likely or practical to base the success of your franchise around doing so? no.
If 7th round pick Tom Brady was to be re-drafted, where do you think he would be taken if we could re-do that draft?
If the Bills are sold on "QB X" being the next big thing, they better do EVERYTHING within their power to secure such an important asset to the organization.