There's an interesting post in the german forum which explains the mathematical nature of it^^
you may want to use google translator for it
Warning, google translator not perfect
That being said, I read it and it said exactly what I (and many others) have been saying for a long time...
Just because you have gone through a bad luck stretch does not mean the system is broken.
Every attempt has a 20% chance of success and an 80% chance of failure. The probability of success never changes, but the probability of continued failure does decrease but never reaches zero.