They do produce a lot of good players. Do you really think they would be spending so much on it if there wasn't anyone coming out of their academies.
The fact that they might end up at another top league club not Chelsea is irrelevant
Chelsea are currently under investigation for illegally hoovering up the very best young players from all around the world. I'd be very disappointed if they weren't producing a lot of good players, as it looks as though they have been gaming the system for quite a while.