RNG! 
After everything is affected by RNG, you go an extra level and add RNG on top of RNGs, like Hearthstone… $Profit$
Seriously though… The only successful game that makes no meaningful use of RNG in gameplay that I know of is Age of Empires 2.
(AoE2 still uses RNG on world map generation though and often on tournaments 1x1 players would request a restart due to unfair map generation)
Game designers in this last decade learned that players ‘hate RNG’, but it’s a key element to keep them hooked and coming back often; sucks but true.