The White House’s estimate of gains for the average American family rests on a lot of assumptions and is disputed by economists on the right and left alike.
It might just have to do with simple math. Average out the amount of money the rich get, and include the rest of us in that average, and you may get $4,000. But DON’T include the rich in that average and you probably get zero.
Look at it a different way, if Bill Gates walked into a bar that had 88 broke people in it, the AVERAGE wealth of each person in that room would be $1 Billion!