We have evidence of scientific and engineering advancements spreading from space programs out to the world. We also have evidence of trickle down economics not working. What more do you want?

(The biggest difference to explain that, I would say, is that a scientific/engineering advancement can deliver value magnitudes greater than development cost, but trickle down at best transfers some of the money. And that's what most of the budget is going into on a project like this, not basic equipment assembly or the proportionally tiny fuel cost.)