Every year there are people who beat the indexes and there are people who perform worse than the indexes. Every successive year some proportion of the winners stay winners and some become losers. The interesting thing to note is that—if you look at the statistics—winning one year has almost no bearing on whether or not you win the next year.
Still, there are participants who flipped that weighted coin year after year and caught heads five years in a row. It doesn't mean they have a successful strategy. It just means that if you flip a 45/55 coin five years in a row, two out of one hundred people will get a string of heads.
I've personally witnessed all of my day-trading friends go through this (I almost said "learn this lesson" but I'm not sure they have). For a while they beat the index and they're convinced their strategy is sound. One day something unexpected happens and they're suddenly in the hole. Often this is compounded by having an enormous tax bill on "gains" that no longer exist, necessitating selling off holdings that are deep in the red, making it even harder to get back to positive.
Do some individuals exist who can reliably beat the markets? Sure. They just are exceedingly likely to not be you, and none of them are offering their services to you.