You're assuming costs have remained the same for goods and services consumers demand. The cost of electricity is plummeting due to renewables, digital services and IP have zero marginal cost, Moore's Law, etc. People are eschewing cars, and in the next 5-10 years cars will be a service, not something you own.

The issue is there are still inelastic demand services that need their costs driven down drastically: Education and healthcare. I'd also suggest petroleum being displaced for transportation as well. Reducing the cost of these services reduces the amount of work needed to consume said services.

I argue an 11-15 hour work week is still possible as technology and innovation continue to move forward.