The European champions were eliminated in Brazil at the group stage, receiving a 5-1 thrashing from Netherlands before Chile sealed their fate with a 2-0 win.
The Spanish Football Federation (RFEF) elected to keep faith in former Real Madrid boss Del Bosque, who guided the team to world and European titles in 2010 and 2012, and he is looking to re-build going into the European Championship in France in two years.
"The World Cup wound hurts, but we must look forward and fight for a better future," he told Onda Cero.
"The Federation has never had any doubts surrouding my renewal. The six years outweighed the game that we lost. I understand the fans' reaction, when you lose they will usually go against the team and the coach."
There were some suggestions Del Bosque should have called up some fresher faces to his World Cup squad rather than stick to the veterans of past tournaments, including Xavi and Iker Casillas.
Del Bosque, however, insists he would not change his selection given the chance.
"I wouldn't make any changes to the 23 we had at the time. Maybe we failed, but we did our best. They are outstanding players, heroes who have given us a lot of what we have."