A well is not a container. It's a place where water arrives, slowly, from somewhere else, on a schedule that has nothing to do with your plans for it. You can empty one in an afternoon and find it filled again by morning.
That's the useful sense of limitless. Not that a life runs at one pitch — none of them do — but that running dry on a Thursday is no evidence at all of a permanent shortage. The recovery is the part worth trusting. Most of what feels like a lack is simply a well that has been drawn on hard this week.