Johnson was reportedly tracked by Chelsea and Manchester City, two clubs whose owners have contributed to spiralling transfer fees for top players.
Since he bought the club in 2003, Russian billionaire Roman Abramovich has supplemented Chelsea's transfer funds with large loans, while City were taken over by the ambitious and wealthy Abu Dhabi United Group in September.
Barry, 28, who came close to joining Liverpool last summer, became the latest big-money arrival at Eastlands as he followed Roque Santa Cruz, Jo, Robinho and Craig Bellamy in an £12m move at the start of June.
"City have signed a lot of good players, but that is no guarantee they will win anything. But it will be interesting to see what happens next season," said Benitez.
Benitez is now bracing himself for big-money bids from La Liga giants Real Madrid and Barcelona for Xabi Alonso and Javier Mascherano - although he is determined to hang on to the pair and hinted that they owe Liverpool a debt of gratitude.
He said: "I do not think Alonso or Mascherano will go. It is clear that they both are under contract with long-term agreements. That is it.
"There has been a lot of things written, a lot of rumours, but both players are under contract and we have no more need to talk about things.
"They are both very good players and I will be very pleased to keep them. They both have very good contracts.
"We signed them both from different situations. Alonso was coming from Real Sociedad and nobody had really heard much of him outside of Spain, he did well and we renewed his contract because of that.
"Mascherano came from West Ham where he had not been doing well. We brought him here and gave him a good contract, so we are very pleased with them both and that Liverpool has been very good to them."
The summer's most spectacular spending has taken place at Real Madrid, where Benitez spent his early years as a coach.
Cristiano Ronaldo, Kaka, Karim Benzema and Raul Albiol have been recruited at a combined cost of about £183m, but the Reds boss warned that building a team through the chequebook is no guarantee of success.
"Things have changed. You have to adapt to a situation. Manchester City and big clubs in Europe are spending big money, so the market has changed and we have to work harder," he added.
"If you spend big it is always easier to perform well. But when you have a good understanding between players, that is also important. If they are together, they work hard, that is just as important."
E-mail this to a friend 
Printable version 
Bookmark with:
What are these?