As we saw with cristiano ronaldo, if you're good enough you will make it. i know that is a crazy high standard to reach, but he played for sporting (not a big club) but he worked his ass off to stand out and be arguably the best player in the world. when chelsea send players on loan they expect the player/s to impress, if they don't do that then they are obviously not cut out to make it at chelsea. one example is traore, he went off to vitesse, did decent, came back and had some cameos but didn't impress much, so we sent him to ajax, but he's turned out to be abysmal.
it is the players' fault if they cannot work hard and impress. the other problem is the young players earning so much at a young age. what incentive is there for the majority of them when they can go on loan to a mediocre club and get paid well for doing so? the stand out players are the ones who work hard, show dedication and impress when given the chance to do so. i know for certain, if ake gets called upon he's going to do a job for us, because he's just naturally a quality young player. he may never be "world class" but he's a good, solid young defender at the moment.