Between land, hardware, having to build multiple power plants, the labor costs involved in all of this, and setting money aside to run all of those for however long, then yeah I can see where it gets up to that price. 20k engineers is easily 5 billion per year in salaries, probably more.
Assume the human resources at $100,000 per head, and you get $2B/yr. Four years comes to just $8B for human resources. Assume land costs $10B. Assume construction costs $100B.
