No, it's a strong argument. For Benitez never had a ****load of money at any one time to spend on great players. He had to buy cheap players and take punts. He'd manage some success (CL, FA, whatever) and then sell those players for slightly more and try to get a slightly better player. That kind of team enhancement not only takes years it means such a figure as simple net spend will grow to a big number without the fact that we've ever had the spending power it suggests.
And people don't realise that Benitez/Liverpool compete with the teams that exist now, not only the players that were bought by United/Chelsea/etc since he joined Liverpool. And none of those teams spent that kind of money on that many players. None of them have overhauled themselves to the extent we have. I repeat, we only have 2 players left from when Benitez originally joined.
You have to give him credit for the incremental improvements. Our spending is more comparable with Tottenham, yet we've won a CL, gone to another CL final, won the FA cup, have been regularly in the top 4 and challenged for the title last year. We are not spending like Chelsea/United/City on players and do not have squads as strong as theirs. We buy a player like Aquilani for 17 million and are on our knees praying it works out. Meanwhile United have spent that figure several times on players like Nani, Anderson, Carrick, Hargraeves, Valencia, etc.