Do people really think that the model of "Schools as factories" will work? The next step will be to increase the number of hours per day, after Saturday school fails to give the anticipated results.
The "good" news is that this is largely unsustainable as you've got to pay teachers, admin staff, transportation, and provide supplies for all these ambitious activities education reformers keep dreaming up. Schools are strapped for cash as-is. Hell, my old Highschool currently shuts off most building lights in between classroom periods to save on energy costs. This isn't done because the district is trying to be green: it's being done because it's broke.
Ultimately sheer economics will prevent 6-day/10+ hour school days from being implemented nation-wide.