Sometimes that win streak never comes. Check season 33:
There was no major injury. I hadn't lost any major players. In fact, I picked up a couple type As thinking I was on the WS contention path. Everything went wrong all at the same time.
At the end of the day, its still a RNG. You can mitigate the risk by getting the best players possible, but given a large enough sample, you are eventually going to run into occurrences where there is an extended series of results not in your favor. If your team is good, you'll come out of it eventually.