The Monorail was built for the 1962 Century 21 Exposition (Seattle World fair) by the Alweg Monorail Company. Alweg ran it during the fair and fully paid off the 3.5 million needed to build it and made a profit. At this point they gave the monorail to the Century 21 corp who ended up selling it to the city for $600,000.

It is actually bolted to its foundations in a way that allowed for it to be taken out at the end of the expo.

My guess is that Alweg’s plan was to build and make profit on the monorail for the three years outlined in their contract, and they were worried about eating into their profits if the City of Seattle required them to remove it afterward. so they made it easy to remove.

Also, Alweg also offered the city of Los Angeles a monorail with 40+ miles of track, for free. The deal was they would build it, and run it for 3 years, like the Seattle one, and would give it to the city of LA afterwords for free. The Auto and Tire companies unfortunately successfully scrambled to block it via the political arena.