Some teams have had an embarrassment of riches at the most important position in the game: quarterback. The Packers basically went from Bart Starr to Brett Favre to Aaron Rodgers. The 49ers went from Joe Montana to Steve Young. The Patriots had Tom Brady—who is better all by himself than all the quarterbacks that some teams have had in their entire history combined. Super Bowl wins and enshrinement in the Hall of Fame are normal for some franchise's quarterbacks.
Not so much for the Eagles. If you look at the Hall of Fame, the Eagles don't have a single quarterback who spent the majority of his career playing for the franchise.