We live in an Instant Society:
Microwaves can heat our meals in minutes On demand TV Instant Messaging Google for answers in microseconds 24hr shops Next day delivery
If we want it there is a good chance we can have it NOW.
When I was younger it was a bit different ... and we were used to waiting for things. Today's children so often do not need to wait which is why I believe gardening is such a good activity for them.
It teaches patience and good things come to those who wait. Vegetable gardening shows children where food comes from - it may also help fussy eaters to enjoy their greens (and reds and yellows ...)