Only sorta random. Lumen Field, where the Seahawks (NFL) and Sounders (MLS) play, and T-Mobile Park, home of the Mariners (MLB), one block south are pretty much under the north approach for KSEA. If you extend the centerline of 16R you end up passing about 1100m (.6nm) east of the stadiums. Sitting on the 3rd base side of T-Mobile for an evening game is great, the seats are shaded by first pitch and you can look up over the retractable roof to watch the planes go by, while also enjoying a baseball game.

The location of Seattle (and especially downtown) relative to KSEA's runways is also why the Columbia Center is likely to remain the tallest building in Seattle for the foreseeable future. Any taller and the FAA would stop it because you're getting up into the flight path.

KSEA also can't put in a 4th+ runway facing more east-west because of the topology of the area, the whole Puget Sound region was carved out by retreating glaciers, so going north-south is relatively straight forward, follow the ridgeline or river valley floor, going east-west means a LOT more earth that needs moved.