Only $3.5 billion to produce 1,000 metric tons of propellant on the moon? Seems like it probably would have already been done by now if it were that cheap. Wou

Only $3.5 billion to produce 1,000 metric tons of propellant on the moon? Seems like it probably would have already been done by now if it were that cheap. Would it not make more sense to build safer and more reusable systems, like, electromagnetic launchers?