It is difficult to take much of anything away from Beckett's work. Many have tried, and I think that the general nature of the work is like a rare bird. One is to appreciate its beauty, its uniqueness, and distinctive nature from all others. There is a grace and a certain level of pride felt when such a bird flies in your garden. Yet, to try to capture it and contain it denies its essence and it is here when it flies away. The idea of "inaction" is something that plagues the characters in Beckett's work. Paralysis is of vital importance as it is the result of their waiting. When we abstract this to a larger sense, it is evident that many lives are spent in such waiting, such paralysis. Vladimir and Estragon are mocked in many lights for their lack of action in waiting for Godot. Yet, in broadening this out, many others "wait" for a dinner guest who has never arrived and probably never will. This is in our professional lives, waiting for a promotion, for a sale, for the financial break which will solve everything, but rarely does. This is in our personal lives when we wait for that great and perfect alliance, or when we ignore real action and discussion in our relationships because "things will improve." The notion of inaction is one presented in the play as an easier alternative and natural one that can be embraced in the place of the much tougher and much more arduous of taking action, living with consequences.
Just to add to the answer already given, I would like to create a counter-pattern in emphasising action and especially the continual going on in Beckett's work in general. This is an against the grain take on what happens in Beckett as opposed to that which does not, as popularized by philosopher Alain Badiou.
I think, Beckett's work is not primarily about passivity and inaction; it is rather about the will to go on when it becomes impossible to go on. Remember the last lines of his novel The Unnamable ---"You must go on, I can't go on, I'll go on." The continuity at the wake of its impossibility, action at the wake of inaction, the redefining of mobility as against the backdrop of immobility is the condition here. The crawlers never stop in How It Is, the movement continues in plays like Come and Go, Footfalls and What Where even when there is a lethal circularity to them. The 'on', in its subversion of 'no' explains the paradoxical doublet of action and inaction in Beckett.