You didn't really expect to sign up for a free membership and automatically get all those benefits... for free... did you?

All the benefits you mentioned are for SkyMiles Medallion members. If you fly at least 25,000 miles in one calendar year (Jan 1 to Dec 31) you qualify for Silver Medallion (the lowest tier). Only flown miles count for that threshold - no purchases or bonuses or anything. 50k miles for Gold, etc. You need more than 3 round trips/year between Seattle and Colorado Springs to achieve that.

You definitely misunderstood the idea of a frequent flyer program. You have to fly FREQUENTLY in order to get benefits. (3 domestic round trips/year is NOT frequent.) The US Airways Divident Miles program is along the same lines.

The benefits of a frequent flyer program for occasional flyers such as yourself is that you keep earning miles which can eventually translate into a "free" flight. (I used quotes because they're not actually free - you still have to pay taxes and fees on those, but they can be considerably cheaper.)

My advice: relax, and read the terms and conditions carefully.