There are a handful of different approaches that the Packers could have taken regarding the QB situation.
1. The one they took. Move up to take a guy you think is that good and work the rest of it out-- presumably because you don't expect to be in a position to draft this kind of QB prospect any time soon.
2. Wait at least one more year to start taking shots so as to better fit the rookie deal to Rodgers' gtd money running out. This was the camp I was in before the draft.
3. Just ignore the position until Rodgers retires and figure it all out later.
I obviously completely understand the reasoning behind #2, as it was what I preferred. However, as Pokerbrat has pointed out, you can't choose when a QB prospect that you really like makes it to you in the draft.
The Packers FO probably assumes (and probably correctly) that Rodgers is going to keep the team picking at least in the back half of round one over the next couple seasons. Good QB prospects very rarely make it down into the 2nd half of the round.
Someone might say "ok, well doesn't that mean that Love isn't all that great then, since he made it that far?" and I would say maybe, but clearly the evaluators working for the Packers didn't think so, and their take was the one that mattered. For myself, whatever my opinion is worth, I think Love is a better QB prospect than a lot of guys that have gone top 16 in recent years (e.g. Josh Rosen, Josh Allen, Daniel Jones, Dwayne Haskins).
As for approach #3, I think that idea expects professionals to look at the team like a fan. We might say "let Rodgers retire, be terrible for a year, pick in the top 5, and boom-- you've got your new guy." But the people running the Packers are trying to keep the team competitive, and they're trying to keep their jobs. It's unlikely they would survive a total tear down, and again, that approach would require the right guy to be there for them in that year that they were bad. What if you're terrible for the draft year that Blake Bortles or E.J. Manuel is the top QB prospect?
I think the bottom line is that Gutekunst saw what he believed is a succession plan to secure the future of the organization, and he decided to take it despite the timing not being very good, because the pay off would be worth it.