Liverpool made, overall, a nice profit on Benitez's purchases... but he:
A. inherited a squad worse than Everton's at the time
B. he was never backed in the same way Ferguson or Mourinho were backed; but he was, indeed, backed. Let's compare them to Arsenal: Wenger also is a proper manager, but he was never backed in the same way as Chelsea or Utd. He didn't win the league after 2003....
The names you come up with prove that point: decent players were not enough to win the league.
Crouch was sold at a profit. Never a failure.
Pennant was decent, not great. 6 million.
Don't even know Leto or Cavalieri. They can't be that important.
Babel: decent enough, sold at a loss
Dossena: cheap but effective
Keane: fail
Riera: fail
Glen Johnson & Kyragiakos: both decent but bought when things were looking bleak in the boardroom (if memory serves)
You forgot N'Gog though!
His hands were also tied by boardroom decisions, I read last month how he was forced to use Jay Spearing instead of signing Aaron Ramsey at 17....
We'll see. He's proving you wrong though.