their playstyle is very big performance/hero plays reliant (unless they face a worse opponent) so against big strong teams it wont work constantly. (FNC, EG, Loud today) if they end up on a situation like Lotus was, without crazy hero plays they would have lost pretty badly.
This wasnt the case as their roster is brilliant individually, but you cant really rely on 2/3 players popping off and pulling rounds out of their asses every game.
Therefore, PRX wont win champions because they cant replicate this heroic performance every single tough match they have.