Jim is, very simply, having the right amount of available inventory when needed. That’s the basic premise. If you can remember that, then you can understand this whole phrase.
This is useful not only because the stock is vital to have but having a proper inventory is much easier to manage and scale according to market demand than desperately trying to gain more units or offload from warehouses before they become obsolete. Like the E.T. game, you would be forced to bury all of it in a Nevada desert.
The significant risk of only carrying enough is that if the forecasting fails to come true, a company can quickly become short-stocked and fail to meet the demand, leading to long waiting periods and customer discontent.