I agree with your premise that you need to get a franchise QB and then you can be consistently competitive for an extended period of time. However, once you have that the other pieces do also matter. I absolutely disagree with "The QB is all that matters", you need coaching, strategy and the right guys at the other posititons. It is much easier to get the "right guys at other positions" once you have a QB. The decision to draft Love is strange given Rodgers age and reasonable expecation to play another 4 years. Unless the Pack is strategizing to move on or Rodgers has given them a time frame it was a bad decision in my mind. You surround that franchise QB with as much talent at the other positions as you can. Drafting a QB in the first round does not do that. So you are both kind of right.
Just because the Chiefs sat Mahomes for a year does not mean he would not have performed as a rookie. And overall the Alex Smith/Mahomes thing is totally different than Rodgers/Love. Rodgers is one of the best of all time, Smith is average.