If you read the article, it mentions the point about the magnet costing10 times more to build / assemble on-site.
That's not precisely what the article said:
"It costs about 10 times less to move the magnet from Brookhaven to Illinois than it would to build a new one," said Lee Roberts of Boston University..."
My point is that it would cost even less to move the magnet if they did the final assembly after shipping the component parts closer to their final destination. It's the same process we used to build the space shuttles.