The key to their success was also their undoing, low cost was the mandate of Walmart
not dependable; now yes, now no; always changing
Etymology
In the beginning of the Han Dynasty, Xiao He recommended Han Xin become a general, later he helped Empress Lü Zhi to have him killed. Later, this phrase was used as a metaphor to describe a situation in the success or failure of an endeavor derives from the same person or thing.