Trickle down economics has one purpose only

And that is to make the rich richer. The recent tax scam makes it perfectly clear. Corporations have used the extra money to buy back their own stock, thereby increasing its value so that the owners get even more money. Any small bonus they gave to their employees was one-time only, and wages remained flat. Walmart indeed gave a bonus but then fired workers, saying they could be rehired but at a lower wage. At the link see the World Inequality Lab report, which debunks the myths of tricle-down.