He said: "Where Capello has been quite fortunate is that he's nearly always had the best players available.
"I feel as though that is where England have fallen down over the last 10 years. When our top players are injured and not available we do not have that next generation, that next best player, to come in and replace them.
"That's why people like (Rio) Ferdinand, (John) Terry, (Steven) Gerrard and (Wayne) Rooney are really important to the England team. You do not want them injured for important games."
Robson also believes the players are growing in stature under the stewardship of the Italian coach.
"He is doing a great job - you only have to look at the performances and results, " he said. "All you can do is the job that is in front of you.
"Fabio has done that well and the England boys are very confident. That's great because after the disappointment of not qualifying for the last European Championships it is really important to qualify for the World Cup."