QPR were relegated following their goalless draw against Reading on Sunday.
The Royals were also condemned to relegation following an uneventful 0-0 draw at the Madejski Stadium, meaning both sides will now play in the npower Championship next year.
Redknapp replaced Mark Hughes at Loftus Road in November with the club already cut adrift with just four points from their opening 12 games.
The former Tottenham boss admitted the club needs work but that a clear-out of big-name players on good money will not be an easy task over the summer.
"There are problems within the club," he conceded.
"It is not easy to change when people have got contracts - I've heard over the years that players will want to leave because you have been relegated but where are they going to go?
"If they had played better perhaps we wouldn't have gone down,. one or two will be wanted by good clubs.
"There are an awful lot here that have good contracts and it would be hard to get rid of them even if I wanted to shift them. You can't shift people on two or three-year contracts for good money.
"It has not been an easy club to manage, but if it had been easy I wouldn't have got the job. They offered me the job because that is the situation they were in, otherwise I wouldn't have got the job, Mark would have still been sitting here now.
"I'm only concerned about the owners of the football cub. QPR are not a super power going into the championship."
He also acknowledged he expected a tough season in the fight for an immediate return.
"QPR have got no divine right to come back up next season," he said.
"You will see 14, 15, 16 clubs in the Championship who have won things - Notts Forest, Derby, Leicester, Blackburn, Burnley were a big club in the 60s - all big clubs in the Championship - we are going into it next year and it will be hard to get out of it, make no doubt about that.
"There is a whole lorry-load of them, Leeds United one of the greatest clubs in football history, there are massive clubs in those division.
"Winning is a lovely habit but it is very hard when you have been losing all year and you are expected to win every week."