The problem is demand which is what the middle/poor class provides... assuming they have the money to do so. Creating a new product doesn't create demand unless it is something technologically innovative or whatever. It might squeeze out another company, but it does not create new demand just because it exists. Rich people don't create jobs, the economy does, and for that to happen the wealth needs to be somewhat reasonably distributed.
Instead, we have lawmakers in the pockets of the wealthy and creating laws protecting them or removing laws protecting everyone else have eroded the middle class and led to stark decreases in middle class ownership of the economy. A yyuuge tax cut isn't going to change that trend.
