Rated major contenders a year out from the tournament, Ireland crashed out of the quarter-finals with a 46-14 thrashing by the All Blacks on Saturday, continuing their record of never winning a knockout game at the global showpiece.
"If I had one regret it's the fact we talked about (the World Cup) a year ago," the New Zealander told reporters after arriving back in Dublin.
"We built up to it and we probably went away from our week-to-week focus or our immediate tournament focus.
"Maybe we built it into something that became a bit of a self-consuming monster because we didn't play as well as we could. I have to take responsibility for that.
"If I had my time over I might do it a little bit differently. Unfortunately my time is done."
All the same, the disappointing World Cup has not greatly diminished the market appeal of a coach who took Ireland to three Six Nations titles and the Grand Slam in 2018 in his six years in charge.
Schmidt, who will be succeeded by assistant coach Andy Farrell, said he had been "blown away" by offers of coaching positions but would not entertain any until the middle of next year.
"I know I’m not going to do (coaching) in the near future," the 54-year-old said.
"I made a commitment that I’m going to absolutely stick to, through to at least June or July of next year.
"It hasn’t been a job, it has been a way of life. It has been seven days a week and I think I can honestly say, in six and a half years I’ve not taken one full day off."
Schmidt's comments may disappoint some Australian rugby fans as the Wallabies look for a successor for Michael Cheika, who resigned a day after their own quarter-final exit from Japan.
Schmidt said he would enjoy being a spectator for a change and expected Farrell and the Irish team to continue to do a "super job".
"I’m really looking forward to the Six Nations," he added.
"Instead of looking through the glass, I might just have one in my hand and I’m looking forward to that."