Correct, and that's pretty much how you have to do it. One year of being bad isn't falling off a cliff by NFL standards. Its when you lose your franchise QB and spend 5-10 years or more looking for a new one that you fall off a cliff. There will certainly be growing pains when Joe leaves, and not even using a mid round pick on a QB this year is going to stop that.
People like to pretend to think the Patriots are geniuses for drafting guys like Mallett or Garoppolo that early in the draft, but the reality is that any production Garoppolo has in this league is almost certainly not going to come in a Patriots uniform. They used a second round pick on a player that, if everything goes well, will have basically never played for them. They are about the only franchise I know that has that luxury, and we certainly don't.
I do find it funny that fans think that this is somehow something that all teams do... they draft a mid round QB and let him sit for a few years while he learns how to become a starter. The last success story I can remember off-hand (and there could be others I don't remember) where that actually worked was Rodgers (and he was a 1st rounder, not a mid rounder), and you're looking back over 10 years at this point.
So in over 10 years nobody has successfully done that. Have fans ever asked themselves why that is?
I'll give you guys a hint... the value of QBs in today's market is almost strictly limited to their first 4-5 years in the league. That's when they can play at a high level and get paid very little for it. If the objective is to draft a guy who won't play for 3-4 years and then will all of the sudden play well, you're getting MAYBE 1-2 years of actual cheap value out of them. After that, you've got to pay them $20M+ a year, and it affects your roster construction in a big way.