It is an illusion to think we will be less busy in the future, or at any point in the future, than we are now.
There may be particular instances where this is not true, in other words, exceptions to this rule, but these exceptions are themselves deceptive tricks of the mind, in most cases. In other words, the fact that there are many apparent exceptions simply perpetuates the fallacy of future time.
Take the notion of winter break. If we postpone things for the break, then the break is no longer a break, but an equally busy time filled with all the tasks that couldn't be accomplished because we were too busy during the semester. In fact, we are too busy during the semester because we are always putting things off until other times when we are supposed to be less busy. The same goes for a weekend or, on a larger scale, the summer.
I asked my colleagues to propose names for a lecture, giving them a week to come up with some names. I get an email back saying that might not be enough time, given how busy we all are with a search, a third year review, etc... The time it took to write that email is about the same amount of time it would have taken this person to send me a name of a prominent Hispanist who might come and give a lecture next year. Everyone knows the names of prominent people in their own field off the top of their head. I would also need time to send out a new message with a new deadline, so apparently to postpone a task until we have more time to do it simply makes the task take more time for everyone. Also, a longer deadline would make people less likely to meet it, because there is more time to forget.