Why must they discontinue?

If you don't know by know I Love yarn. I am 100% fiber lover. I always have at knitting or crochet project going (sometimes both at the same time), and picked up some new yarn recently (Mon, March 9 exactly.. don't ask me why I remember this stuff) at my local Robert's for a later project. I'm short a few skeins, which doesn't bother me... that's what the internet is for. So today, I jump online eagerly to scope out the best deal on the remaining yarn I need for the project when to my mild horror.... it's discontinued and every search for the yarn I try yields NOTHING! Tomorrow, I am going to go to Robert's and buy the last of what they got for that yarn.. no matter the color (for the most part) I make a stripe project is stead of a solid color... and if they're out.... To Ebay!