Trickle down does work, but it depends on the economic environment you're in. Percolate up does too, but works in different environments.

It's a question of supply and demand. Say's Law, as Keynes put it, is that demand creates it's own supply.

This is only true for ESTABLISHED markets.

In emerging markets that have yet to be fully created, then there is no demand at all. In those cases, trickle down (or rather, supply-side) works. That is why China is growing like mad, despite that they're using supply side economics. They don't have established markets yet (they're about there now).

So, basically, it's not a one size fits all situation. In say the retail sector, or in manufacturing like the auto industry, then percolate up creates far more growth, and sustained healthy growth than trickle down.

In emerging markets, like say new technology (green energy, bio-tech, some computer sectors), then supply side is the way to go.

In the USA, since the vast majority of our markets are already established, then if you have to use a one-size-fits-all policy, then you will get more growth with percolate up.