All of this assumes there is a cirulating line. The last item will get hot last is not brilliance, it is a fact. If it is a circulating line then a properly operating pump would give hot water everywhere equally. If it is an incomplete circulating system, which I run into quite frequently, without a pump, then the installer is using the kitchen sink as the circulator device, assuming that the sink is used most frequently and therefore will keep the rest of the piping supplied with hot water. A bad pump and a bad check valve on a recirculating system can allow cool water to backflow to the last fixture on the loop and then it may never get hot water.