What is the evidence that trickle down economics actually works?

[$tevie]

rankandfile wrote:
There has never been a better time or need in my lifetime to invest in our infrastructure which has deteriorated so badly. We have depreciated it beyond safety in many cases. It's an investment in the future.

Those 1960s non-redundant bridges that were all the rage to talk about after the bridge collapse in Minnesota in 2007 are all still non-redundant and all still ticking time bombs. I can't for the life of me figure out how that can't translate into large projects that will be profitable for the contractors and create jobs for any qualified folks who are currently unemployed.