"Trickle Down Economics" isn't an actual economics theory, just a buzzword leftists use to denounce rightists or mainstream economics.

Show me one economics textbook that has the term "Trickle Down Economics" in it. You can't, because there isn't one.
Consumer spending doesn't create a good economy - it is the *sign* of a good economy. There's a difference.
As for Bernie Sanders' "free everything"

- as was said above, how did that work in Venezuela? And when you consider that Venezuela is sitting on the largest oil reserves on the planet, that is really an impressive achievement in failure - even for leftists.