You know that that's not how this works, right? The bulk of the population is paid at a rate that is just this side of starving because it's the least that the capitalists possibly could pay them and still have people working for them. Something like this, i.e. an expansion of working hours, would mean nothing in the long term but the ability to pay workers less because "they can just supplement it with their sleep job" which will probably pay not very much either, looking at how little gig economy work really pays.

If we can be made to work during sleep it will never be in the detriment of working during the day.