Assuming equal probability distribution among all teams over a sufficient amount of time, the odds of the Seahawks winning the Super Bowl in a given year are 1/32, or 3.125%. Under the same conditions, the odds of the Mariners winning the World Series in any given year are 1/30, or 3.333%.
The following is a list of probabilities based on those two numbers, along with the assumption that expansion and contraction don't occur in either league.
Seahawks don't win in a given year: 96.9%
Mariners don't win in a given year: 96.7%
Neither Seahawks nor Mariners win in a given year: 93.6%
Seahawks win, Mariners don't: 3.0%
Mariners win, Seahawks don't: 3.2%
Seahawks don't win within next 5 years: 85.3%
Seahawks don't win within next 10 years: 72.8%
Seahawks don't win within next 20 years: 53.0%
Seahawks don't win within next 50 years: 20.4%
Mariners don't win within next 5 years: 84.4%
Mariners don't win within next 10 years: 71.2%
Mariners don't win within next 20 years: 50.8%
Mariners don't win within next 50 years: 18.4%
Neither team wins within next 5 years: 72.0%
Neither team wins within next 10 years: 51.8%
Neither team wins within next 20 years: 26.9%
Neither team wins within next 50 years: 3.8%
Neither team wins within next 80 years: 0.5%
The depressing way of looking at all this is that there stands a roughly one-in-a-hundred chance that I don't see a Seattle championship in my lifetime (the Sonics don't count because, well, I hate the NBA, and think it sucks). The sunnier viewpoint is that the odds of either the Seahawks or Mariners winning it all in a given decade is essentially a coin flip, meaning that, were the decade to begin right now, I'd have roughly a one-in-two chance of seeing at least one of the teams bring home a trophy before I get cranky and bald (which I expect to happen once I hit the big 3-0).
In image form:
Speaking strictly in terms of general probability, the Mariners have a slightly higher chance of winning the Series than the Seahawks do the Super Bowl because there are fewer teams in the MLB (30) than there are in the NFL (32), but at least as far as the next few years are concerned, you probably can't think of it that way, because the Seahawks are at the top of the NFC while the Mariners have a ways to go before they look like a legitimate title contender. So in that respect, this kind of graph doesn't really apply to the short-term because of the other variables involved.
So, yeah. I'd love to move on but I get the feeling like yesterday's going to be bugging me for a long time. Having one of my favorite teams even make the championship counts as progress, since none of the Mariners, Seahawks, or Ottawa Senators have managed to do that during my lifetime (or, y'know, ever), but it's tough to see a team fall short of the trophy when you know they could've had it if they played just a little bit better. And it's harder to stomach than it is with baseball, where the losing team has to drop four games to bow out instead of one, because in the latter case a team gets several opportunities to play at its best, whereas in football, if you don't come out of the gate and establish your tempo early, you probably aren't going to find it before time runs out. It happened to the Seahawks, and just like that, the season was over.
Maybe next year.