But now, I wonder how he intends to capitalize all this success. I don't think that Littlefinger had a remote chance to screw the Starks and the Lannisters and get away with it. Tyrion knows his game, and I think Cersei is beginning to suspect it. The Lords Declarant of the Vale don't intend to let him rule the Vale for long years. He succeeded in corrupting them, but has the loyalty of none of them except Lord Nestor Royce. Varys has a long-term plan which is to have Aegon rule Westeros. Littlefinger doesn't seem to have one: playing the game for playing the game is not one, I'd say.
- He cannot hope to rule Westeros, nor to be the puppetmaster behind Sansa or Aegon. Sooner or later, his role in the downfall of House Stark and Lannister will be discovered and he'll have a hard time saving his ass.
- He doesn't have an army: he's Lord of Harrenhal, but has never been there to rule or anything else. He doesn't have a family, so forging alliances might be hard for him
- He relies on sellswords and hedge knights to protect him but their loyalty goes as far as their life not being at risk.
- In a very martial society, Littlefinger is quite the ugly duckling. I don't think that he can swing a sword, even if that isn't much important.
- He has no charisma, cannot inspire loyalty and doesn't seem to care for that. Plus, I don't think that he can manipulate Sansa forever. Sooner or later, she'll know the truth and that little strangler in the hairnet might be to use.
- Aegon's arrival in Westeros could change the game for him but Aegon is Vary's protégé. Even though they respect each other, Varys could see sly Littlefinger as a danger to Aegon's rule and peace "for the children".
- Stannis knows of Littlefinger's embezzlement and has no love for him.