https://www.numberfire.com/nfl/news/9048/the-green-bay-packers-backup-quarterbacks-have-been-ridiculous-through-the-years
The "heir-apparent" move doesn't even work half the time. QBs wash out which is why taking a few stabs at it is necessary and you can't plan on the first swing hitting. If you get lucky and it hits you have options - like they did with Hasselbeck, Brooks, Brunell
Wikipedia "Hasselbeck joined former head coach Mike Holmgren and the Seattle Seahawks on March 2, 2001. The Packers traded him, along with their first draft pick (17th overall), to the Seahawks for their first (10th overall) and third-round draft picks (72nd overall)." - Not bad use of your 1998 6th round pick
Wikipedia "The Packers traded Brooks and tight end Lamont Hall to the Saints for linebacker K. D. Williams and the Saints' third round pick in the 2001 draft ahead of the 2000 season" - he was a very late 4th round pick in 1999 for the Pack.
Wikipedia "Mark Brunell was selected by the Green Bay Packers in the 5th round of the 1993 NFL Draft. " "After two years with the Packers, he was acquired in 1995 by the Jacksonville Jaguars, in a trade for a 3rd round and 5th round pick in the 1995 draft." - turning a fifth round pick into a 3rd and 5th round pick in two years = not too shabby.
As an organization they have gotten good value being perpetual lurkers in late rounds for QB talent. Many don't pan out but a disproportionate number do.
As for Rodgers - he can be considered lurker value "Rodgers's slip to the 24th selection and the Packers choosing to pick Brett Favre's future replacement became one of the biggest stories of the draft, though he was still the second quarterback selected. His drop in the draft was later ranked number one on the NFL Network's Top 10 Draft Day Moments. Many teams drafting between the second and 23rd positions had positional needs more pressing than quarterback." - AND they were in a position to seriously start looking for a successor/legit back up plan.