On my draft value chart, Seattle moving from #40 to #60, along with giving up a 3rd rounder next year, is roughly equal to the 77th pick. From 1990 to 2000, there were
231 players drafted between pick 67 and pick 87. Only 129 of those players were their team's main starter for even one season; the median number of games played was 62. So you can expect, on average, to get a decent depth pick for what Seattle gave up. To me, that doesn't seem like much for a team to risk for a possible QB of the future, especially when there are no good FA QBs available on the market.