Even at a loss!
Since the Xuli Sect itself also produces spirit food, he was very clear about how much profit spirit food could bring.
Forget about a 60% cut, even a cut of just 20% would virtually erase the profit from the spirit food.
Hence, this proposition of a 60% cut was specifically designed to put Shen Fu in a spot.
Only if he submitted and was willing to join the Xuli sect, revealing the method of refining the Spirit Chicken Essence, they would leave him alone.
However, once the Xuli Sect mastered the method of refining Spirit Chicken Essence, there would be no chance for Shen Fu to maintain his current status.
At best, he would just be an ordinary cultivator skilled in Hundred Arts.
Of course, out of consideration of protecting the method of producing Spirit Chicken Essence, even if they take no action against Shen Fu, they can't allow him to leave the Xuli Sect.