Sources have told Recode that Nest made just $340m in sales in 2015. Without any context, that would sound like an encouraging result for the smart home pioneer, but when considered against the $3.2bn acquisition price paid by Google, the consequent $555m acquisition of Dropcam, and a further $300m for Revolv and its hub, Google is getting a very poor return on its $4bn+ investment. But if Nest showed signs of progress, investors could at least feel confident that the tide was turning. However, the past week has seen private disagreements inside Nest and Google spill out into the public. With rumors of looming budget constraints, things don’t look good for Nest’s 2016. Its radio silence doesn’t help it much,…