You can only be persistent in continuing with a failing business if you have an endless supply of additional capital. I have experienced the shortage of funds that I had to consider closing shop. I was also assured that my business is a good idea but my pocket could not withstand the rigors of a financial shortage.As you have rightly said persistence is needed to be victorious, I would not quit a business I have started because of challenges I would remain persistent so far I am assured that the business is a nice idea that would yield profit.