I don't think liam got in because of miley. They met on a movie set that he was already hired on. I'm not sure about his future. He doesn't seem like the next "big thing" as other actors and actresses appear to be when they become successful.
As for the culprit, (assuming you're talking about the breakup) I think miley gets way too much of the blame. I honestly think he was cheating on her or talking to other girls. She admitted on Ellen that her album was an entire story of Liam. In one of her songs she sings about "she was over it the second that she saw her name."
Personally I think she did soul finding in Philadelphia. She went there to work on her album by herself. She was still with Liam long distance but she knew at this point she needed to make a change to be happy. She cut her hair off, worked with rap artists, and rebelled a little bit. He probably didn't like this side of her, but she was doing what made her happy and then they grew a part because of it.
God one minuite he's playing Thor next minute people claim its Cate Blanchette reciting Shakespeare just because he talks in an eloquent english accent.
The only thing he has is the Sam Worthington factor which is the look. They both have squinty eyes, squinty eyes makes every situation look real hence making the movie believable??_.
Clint Eastwood paved the way for squinty eyes for americans back in the day but it went out of style , now the future of the squinty eyes belong to the aussies OI OI OI!!!
And who's the culprit- Miley or Liam?