Liquid's problem is their play style which doesn't suit international events (short formats). They're famous for their quite greedy splits late into the game, this is quite a streaky play style and averages out over a league like PEL with 100 games played. It also works better when you absolutely know all the teams in your lobby and exactly how they rotate (PEL), international events have more unknowns in this respect.
Add on top of this that they decided to give up their normal drop spots in their Group games it wasn't really looking convincing from them at any stage.
As players they're still top tier, they just need to adopt a different play style for international events and have a defined Plan B if things are not going their way.