Not every olympic lifter trains everyday, but most of those that are competing at the highest levels certainly do.
In my opinion this has a lot to do with recovery from the competition lifts and their derivatives being a lot easier than from heavy squats, pulls, presses etc. So with that high of a training frequency most of the volume will be from explosive lifts, which in a typical powerlifters training plan will only make up a very small percentage of the total volume.
Why so much volume on the explosive lifts? Technique is the one thing, psychology and confidence at higher weights is another. Also, doing the competition lifts often gives you more chances for succeeding at PRs. You can grind out a squat PR set when your training plan demands this weight to be lifted. You cannot grind out a snatch. So your day-to-day form has a higher impact on your daily maximal weight for the snatch and clean & jerk. Programming the quick lifts with a low frequency therefore bears an increased risk of failing pre planned PRs.
All that being said, I am of the opinion that meaningful progress can be made in the olympic lifts even with minimal time spent doing those exact lifts. Provided that one is increasing ones strength base, is reasonably consistent in ones olympic lifting technique, is not yet an advanced lifter (I don't know about those yet) and does not want to compete at the highest levels, in other words nearly everyone, doing the quick lifts heavy 1-2 times a week can be sufficient to produce fairly regular PRs.