The rule of supply and demand: if we restrict supply and growth in demand remains the same, then the price will go up.
If a portion of the network agrees to this, and decides to stop mining for 2.4 hours a day, the difficulty at the end of 2 weeks will not go down by 10%. All that will happen is the difficulty will go down 1%, and you just lost 10% of your earnings while everyone else lost 0%. Does that make it worth it? Hell no.
This idea was tossed about years ago, where they were wondering if a large farm could be more profitable by mining for 2 weeks, and then stopping for 2 weeks. If > 10% of the network shut itself off for one whole diff recalc period, and turned itself on when the difficulty went down by 10%, would the next 2 weeks be more profitable? Yes, those 2 weeks would be profitable, but it would not compensate for the 2 weeks of ZERO income. Over the 4 week period, you would lose out by 45%.
TL:DR
Trying to limit your hashrate to artificially lower the difficulty only hurts you and you're earnings, while everyone else mining 24/7 profits.