Why would everyone be forced to work 10 hour days?

It seems like it only takes a minority of participants to opt for "work longer" to upset the apple cart. 

Imagine there were 10 people, they each got a new magic labor saving device that could 3x their productivity, 8 of them decided to only work 3 hours per day. 

The other 2 decided to work 10 hour days and reap the benefit of effective 30 man hours per day.....what happens?

Seems like everyone would be forced to work 10 hour days?

freetx

I do wonder if we'll finally see a meaningful uptick in leisure with these productivity enhancements. It might be that something like boredom or purpose is driving the 40-ish hour week, more than material necessities.