When we loan players out, in most cases I presume the club borrowing the player pays 100% of the wages. In some cases, we may also get a loan fee. In addition, the player gets a chance to get match practice and gets put in the shop window thus giving us a better chance of higher selling price.
The net result, if things go well, is that we save money on players who are deemed not to have made the grade. e.g., Borini attracted a £14 bid; Coates played well at Sunderland and attracted a bid; Carroll at West Ham?
Given that it's happening so often, I suspect that we indulge in speculative buys. FSG perhaps looking for the kind of profit that Suarez and Sterling provided on player trading. As soon as it's obvious that it's not going to happen with a player they move to cut the losses whilst they go again with the next batch.