A simple point here: productivity growth without wage growth does not provide higher producer income.

If that worker now produces two pairs of shoes in the time it once took to produce one pair but the workers wages do not increase then either:

1. the worker can only afford to buy one of those pairs for his/her own use or

2. the price of shoes must be cut in half

Either way there is no increase of profit to the shoe factory. It is a paradox, but productivity growth cannot be independent of personal income growth. The increased product output must have a market.