I disagree with the they had to pay the qb. The Patriots are the exception to the rule most teams have a 3 to 6 year window of contending for a super bowl.
Not all teams fall off map, but Seattle made a ton of bad draft choices and trades. They are still looking for a running back, they traded a lot to get Jimmy Graham and he was only a red zone threat, they paid a ton for Harvin.
https://en.m.wikipedia.org/wiki/Seattle_Seahawks_draft_history here is a link to their draft history. Go back to 2013 and look at their drafts. You can't draft that bad and expect to stay relevant in the NFL no matter who good your qb is. The Packers, Falcons, Steelers, Panthers, Saints, and Ravens have all given their qbs huge deals and still stayed competitive. I don't have the time, but I would bet if you look at their drafts for the last 5ish years they all have drafted way better than the Seahawks and haven't made as poor of trades as the Graham and Harvin deals.