That is actually a fair question.
The FO had basically 2 options, both of which had risks:
OPTION 1: Sign Flacco to a hefty contract, hoping he will be able to pick up where he left off in his playoff run and carry this team pretty much on his own. Risk being that Flacco fails to live up to the expectations and ties up much needed part of the cap space.
OPTION 2: Refuse to pay Flacco the top dollar and let him walk, hoping you can find and effective replacement for him, in the meantime keeping the rest of the team balanced. Risk being that Flacco keeps playing on high level somewhere else and completely justifies his big payday, while we struggle to find true franchise QB.
Of course everyone is smarter in hindsight. And I'm sure FO did what they thought was the smartest decision at the time. I'm not blaming anyone for the decision to resign Flacco, never have, though I'd love to know more about the thought process that went into the decision. I respect the decision, albeit as it turned out it wasn't the best one. However, it irritates me when people act like Flacco's contract is not the problem. It is very big part of the problem! I would not be, if he were to play as was hoped under option 1 described above. But he is not playing well enough. He needs serious help to play well. We can not afford help, because we do not have the money, big reason for that is Flacco's salary.
It's more than just hindsight here with Flacco and his salary. First, people are forgetting that two very important things happened that altered the success of the Ravens the following year. (1) Ray Rice was expelled from the league - we lost our pro-bowl caliber RB so there went our run game that we were so dependent on the previous year and (2) Boldin was offered a contract according to the value the Ravens deemed he deserved, as such he refused and ultimately was traded. Then (3) Pitta went out with a broken hip. So while we want to say Flacco hasn't lived up to his contract the truth of the matter the entire team failed to live up to their expectations. I really wish people would stop with the Flacco bs; In 2014 Ngata's cap hit was $14 million - did he produce at $14 million - NO!!!! Is that Flacco's fault, NO!!! IN 2015 Ngata's cap hit was $7.5 million and he was playing for Detroit!!!! Flacco's fault, NOPE!! IN 2014 Ray Rice's Cap hit was $6 million and in 2015 his cap hit was $9 million - paid him $15 million to not even play!!!! Is that Flacco's fault, NO!!!! There is so much more going on with this team than just Flacco and his contract.