The weekend as we know it evolved at a time when work was physical and religion was the only source of wisdom.
Back then, 2 days was enough to recover from the physical burden of work. And as much as I detest most of the facets of religion, in this case it made the weekend a time of spiritual commune that had numerous benefits to the soul.
Hence it was the case in the past where you could return to work refreshed by virtue of your routine.
Today's world is slightly different. Many jobs demand hard emotional labour which extend for long hours, sometimes even infringing about the weekend. The combination of hard-to-recover-from work and dwindling spirtual time meant that more and more people were getting more and more tired.
The worst thing about this is that you're caught in a vicious cycle. The weekend provides just enough of a breather for the mind to come back to work refocused, but never is it enough to spur on greater bouts of creativity.
Hence, each weekday is met begrudingly and each weekend is embraced in relief, leaving no time for the measured frustration needed for creativity.
What people need is a long-term, idiosyncratic recuperation strategy. Something that enlivens instead of diminishes one's fulfillment in life. This could be a weekend project that keeps you "creator busy", or it could be a commitment to a weekly family retreat where you're the chef for the day.
Whatever it is, don't fall into the cycle.