Can anyone explain to me the Biden economic theory of "growing the economy from the middle out and bottom up?

The "theory" of trickle down economics was invented by the looney left, no economist or republicans ever referred to it as trickle down. Now Biden rambles on about growing the economy "from the middle out and bottom up" but I would like to know what that even means.

Can anyone explain to me the Biden economic theory of "growing the economy from the middle out and bottom up?
Post Opinion