Jordan Love vs Ian Book

Isn't it the job of the coaches to "groom" players?
Yes, but ideally you would hope your veterans would mentor the younger players. That's what being a good teammate is all about.

Have you watched our preseason games and seen our vets tutoring the younger guys on the sidelines? If Rodgers gets hurt and has to miss 5 weeks he shouldn't want the season to be derailed so his backup being competent works towards his own legacy. There's a reason we were so successful when Drew was out. Neither Teddy or Taysom are undefeated type of starters.